diff --git a/src/main.rs b/src/main.rs
index 8fe3c75..a862186 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -78,21 +78,19 @@ impl State {
         self.mapgen_index = 0;
         self.mapgen_timer = 0.0;
         self.mapgen_history.clear();
-        // Create new builder
-        let mut builder = map_builders::random_builder(new_depth);
         let player_start;
         // Scope for borrow checker
+        let mut builder = map_builders::random_builder(new_depth);
         {
-            // Fetch RNG from resources
-            let mut rng = self.ecs.write_resource::<RandomNumberGenerator>();
             // Build a new map using RNG (to retain seed)
+            let mut rng = self.ecs.write_resource::<RandomNumberGenerator>();
             builder.build_map(&mut rng);
             self.mapgen_history = builder.get_snapshot_history();
             let mut worldmap_resource = self.ecs.write_resource::<Map>();
             *worldmap_resource = builder.get_map();
             player_start = builder.get_starting_pos();
+            // Spawn entities
         }
-        // Spawn entities
         builder.spawn_entities(&mut self.ecs);
 
         // Place player and update resources
diff --git a/src/map_builders/bsp_dungeon.rs b/src/map_builders/bsp_dungeon.rs
new file mode 100644
index 0000000..fb3cdb6
--- /dev/null
+++ b/src/map_builders/bsp_dungeon.rs
@@ -0,0 +1,192 @@
+use super::{apply_room_to_map, spawner, Map, MapBuilder, Position, Rect, TileType, SHOW_MAPGEN};
+use rltk::RandomNumberGenerator;
+use specs::prelude::*;
+
+pub struct BspDungeonBuilder {
+    map: Map,
+    starting_position: Position,
+    depth: i32,
+    rooms: Vec<Rect>,
+    history: Vec<Map>,
+    rects: Vec<Rect>,
+}
+
+impl MapBuilder for BspDungeonBuilder {
+    fn build_map(&mut self, rng: &mut RandomNumberGenerator) {
+        return self.build(rng);
+    }
+    fn spawn_entities(&mut self, ecs: &mut World) {
+        for room in self.rooms.iter().skip(1) {
+            spawner::spawn_room(ecs, room, self.depth);
+        }
+    }
+    //  Getters
+    fn get_map(&mut self) -> Map {
+        return self.map.clone();
+    }
+    fn get_starting_pos(&mut self) -> Position {
+        return self.starting_position.clone();
+    }
+    // Mapgen visualisation stuff
+    fn get_snapshot_history(&self) -> Vec<Map> {
+        return self.history.clone();
+    }
+    fn take_snapshot(&mut self) {
+        if SHOW_MAPGEN {
+            let mut snapshot = self.map.clone();
+            for v in snapshot.revealed_tiles.iter_mut() {
+                *v = true;
+            }
+            self.history.push(snapshot);
+        }
+    }
+}
+
+impl BspDungeonBuilder {
+    pub fn new(new_depth: i32) -> BspDungeonBuilder {
+        BspDungeonBuilder {
+            map: Map::new(new_depth),
+            starting_position: Position { x: 0, y: 0 },
+            depth: new_depth,
+            rooms: Vec::new(),
+            history: Vec::new(),
+            rects: Vec::new(),
+        }
+    }
+
+    fn build(&mut self, mut rng: &mut RandomNumberGenerator) {
+        self.rects.clear();
+        self.rects.push(Rect::new(2, 2, self.map.width - 5, self.map.height - 5));
+        let first_room = self.rects[0];
+        self.add_subrects(first_room); // Divide first room
+
+        // Up to 240 times, get a random rect and divide it. If it's possible
+        // to place a room in there, place it and add it to the rooms list.
+        let mut n_rooms = 0;
+        while n_rooms < 240 {
+            let rect = self.get_random_rect(&mut rng);
+            let candidate = self.get_random_subrect(rect, &mut rng);
+
+            if self.is_possible(candidate) {
+                apply_room_to_map(&mut self.map, &candidate);
+                self.rooms.push(candidate);
+                self.add_subrects(rect);
+                self.take_snapshot();
+            }
+            n_rooms += 1;
+        }
+        let start = self.rooms[0].centre();
+        self.starting_position = Position { x: start.0, y: start.1 };
+
+        // Sort rooms by left co-ordinate. Optional, but helps to make connected rooms line up.
+        self.rooms.sort_by(|a, b| a.x1.cmp(&b.x1));
+
+        // Corridors
+        for i in 0..self.rooms.len() - 1 {
+            let room = self.rooms[i];
+            let next_room = self.rooms[i + 1];
+            let start_x = room.x1 + (rng.roll_dice(1, i32::abs(room.x1 - room.x2)) - 1);
+            let start_y = room.y1 + (rng.roll_dice(1, i32::abs(room.y1 - room.y2)) - 1);
+            let end_x = next_room.x1 + (rng.roll_dice(1, i32::abs(next_room.x1 - next_room.x2)) - 1);
+            let end_y = next_room.y1 + (rng.roll_dice(1, i32::abs(next_room.y1 - next_room.y2)) - 1);
+            self.draw_corridor(start_x, start_y, end_x, end_y);
+            self.take_snapshot();
+        }
+
+        // Stairs
+        let stairs = self.rooms[self.rooms.len() - 1].centre();
+        let stairs_idx = self.map.xy_idx(stairs.0, stairs.1);
+        self.map.tiles[stairs_idx] = TileType::DownStair;
+    }
+
+    fn add_subrects(&mut self, rect: Rect) {
+        let w = i32::abs(rect.x1 - rect.x2);
+        let h = i32::abs(rect.y1 - rect.y2);
+        let half_w = i32::max(w / 2, 1);
+        let half_h = i32::max(h / 2, 1);
+
+        self.rects.push(Rect::new(rect.x1, rect.y1, half_w, half_h));
+        self.rects.push(Rect::new(rect.x1, rect.y1 + half_h, half_w, half_h));
+        self.rects.push(Rect::new(rect.x1 + half_w, rect.y1, half_w, half_h));
+        self.rects.push(Rect::new(rect.x1 + half_w, rect.y1 + half_h, half_w, half_h));
+    }
+
+    fn get_random_rect(&mut self, rng: &mut RandomNumberGenerator) -> Rect {
+        if self.rects.len() == 1 {
+            return self.rects[0];
+        }
+        let idx = (rng.roll_dice(1, self.rects.len() as i32) - 1) as usize;
+        return self.rects[idx];
+    }
+
+    fn get_random_subrect(&self, rect: Rect, rng: &mut RandomNumberGenerator) -> Rect {
+        let mut result = rect;
+        let rect_width = i32::abs(rect.x1 - rect.x2);
+        let rect_height = i32::abs(rect.y1 - rect.y2);
+
+        let w = i32::max(3, rng.roll_dice(1, i32::min(rect_width, 14)) - 1) + 1;
+        let h = i32::max(3, rng.roll_dice(1, i32::min(rect_height, 14)) - 1) + 1;
+
+        result.x1 += rng.roll_dice(1, 6) - 1;
+        result.y1 += rng.roll_dice(1, 6) - 1;
+        result.x2 = result.x1 + w;
+        result.y2 = result.y1 + h;
+
+        return result;
+    }
+
+    fn is_possible(&self, rect: Rect) -> bool {
+        let mut expanded = rect;
+        expanded.x1 -= 2;
+        expanded.x2 += 2;
+        expanded.y1 -= 2;
+        expanded.y2 += 2;
+
+        let mut can_build = true;
+
+        for y in expanded.y1..=expanded.y2 {
+            for x in expanded.x1..=expanded.x2 {
+                if x > self.map.width - 2 {
+                    can_build = false;
+                }
+                if y > self.map.height - 2 {
+                    can_build = false;
+                }
+                if x < 1 {
+                    can_build = false;
+                }
+                if y < 1 {
+                    can_build = false;
+                }
+                if can_build {
+                    let idx = self.map.xy_idx(x, y);
+                    if self.map.tiles[idx] != TileType::Wall {
+                        can_build = false;
+                    }
+                }
+            }
+        }
+
+        return can_build;
+    }
+
+    fn draw_corridor(&mut self, x1: i32, y1: i32, x2: i32, y2: i32) {
+        let mut x = x1;
+        let mut y = y1;
+
+        while x != x2 || y != y2 {
+            if x < x2 {
+                x += 1;
+            } else if x > x2 {
+                x -= 1;
+            } else if y < y2 {
+                y += 1;
+            } else if y > y2 {
+                y -= 1;
+            }
+
+            let idx = self.map.xy_idx(x, y);
+            self.map.tiles[idx] = TileType::Floor;
+        }
+    }
+}
diff --git a/src/map_builders/mod.rs b/src/map_builders/mod.rs
index b52448d..8d11e53 100644
--- a/src/map_builders/mod.rs
+++ b/src/map_builders/mod.rs
@@ -1,6 +1,8 @@
 use super::{spawner, Map, Position, Rect, TileType, SHOW_MAPGEN};
 mod simple_map;
 use simple_map::SimpleMapBuilder;
+mod bsp_dungeon;
+use bsp_dungeon::BspDungeonBuilder;
 mod common;
 use common::*;
 use rltk::RandomNumberGenerator;
@@ -16,5 +18,10 @@ pub trait MapBuilder {
 }
 
 pub fn random_builder(new_depth: i32) -> Box<dyn MapBuilder> {
-    return Box::new(SimpleMapBuilder::new(new_depth));
+    let mut rng = rltk::RandomNumberGenerator::new();
+    let builder = rng.roll_dice(1, 2);
+    match builder {
+        1 => Box::new(BspDungeonBuilder::new(new_depth)),
+        _ => Box::new(SimpleMapBuilder::new(new_depth)),
+    }
 }