diff --git a/day23/day.go b/day23/day.go
new file mode 100644
index 0000000..52d9d85
--- /dev/null
+++ b/day23/day.go
@@ -0,0 +1,98 @@
+package day23
+
+import (
+	"strconv"
+	"strings"
+	"tools"
+)
+
+func run(code []string, register map[string]int) map[string]int {
+	index := 0
+	for index < len(code) {
+		//fmt.Println("Executing line", index, ":", code[index])
+		instr := strings.Split(code[index], " ")
+		switch instr[0] {
+		case "cpy":
+			value, err := strconv.Atoi(instr[1])
+			if err != nil {
+				register[instr[2]] = register[instr[1]]
+			} else {
+				register[instr[2]] = value
+			}
+			index++
+		case "inc":
+			register[instr[1]]++
+			index++
+		case "dec":
+			register[instr[1]]--
+			index++
+		case "jnz":
+			value, err := strconv.Atoi(instr[1])
+			if err != nil {
+				value = register[instr[1]]
+			}
+			if value == 0 {
+				index++
+			} else {
+				jump, err := strconv.Atoi(instr[2])
+				if err != nil {
+					index += register[instr[2]]
+				} else {
+					index += jump
+				}
+			}
+		case "tgl":
+			toChange := index + register[instr[1]]
+			if toChange < len(code) && toChange >= 0 {
+				switch len(strings.Split(code[toChange], " ")) {
+				case 2:
+					if code[toChange][:3] == "inc" {
+						code[toChange] = "dec" + code[toChange][3:]
+					} else {
+						code[toChange] = "inc" + code[toChange][3:]
+					}
+				case 3:
+					if code[toChange][:3] == "jnz" {
+						code[toChange] = "cpy" + code[toChange][3:]
+					} else {
+						code[toChange] = "jnz" + code[toChange][3:]
+					}
+				}
+			}
+			index++
+		}
+		/*
+			fmt.Println("New registers", register)
+			fmt.Println("New code", code)
+			bufio.NewReader(os.Stdin).ReadBytes('\n')
+		*/
+	}
+
+	return register
+}
+
+func Part1(puzzle tools.AoCPuzzle) interface{} {
+	register := map[string]int{
+		"a": 7,
+		"b": 0,
+		"c": 0,
+		"d": 0,
+	}
+
+	register = run(puzzle.GetInputArray(), register)
+
+	return register["a"]
+}
+
+func Part2(puzzle tools.AoCPuzzle) interface{} {
+	register := map[string]int{
+		"a": 12,
+		"b": 0,
+		"c": 1,
+		"d": 0,
+	}
+
+	register = run(puzzle.GetInputArray(), register)
+
+	return register["a"]
+}
diff --git a/inputs/23 b/inputs/23
new file mode 100644
index 0000000..dff3e42
--- /dev/null
+++ b/inputs/23
@@ -0,0 +1,26 @@
+cpy a b
+dec b
+cpy a d
+cpy 0 a
+cpy b c
+inc a
+dec c
+jnz c -2
+dec d
+jnz d -5
+dec b
+cpy b c
+cpy c d
+dec d
+inc c
+jnz d -2
+tgl c
+cpy -16 c
+jnz 1 c
+cpy 84 c
+jnz 71 d
+inc a
+inc d
+jnz d -2
+inc c
+jnz c -5
\ No newline at end of file
diff --git a/inputs/23_test b/inputs/23_test
new file mode 100644
index 0000000..95ee4aa
--- /dev/null
+++ b/inputs/23_test
@@ -0,0 +1,7 @@
+cpy 2 a
+tgl a
+tgl a
+tgl a
+cpy 1 a
+dec a
+dec a
\ No newline at end of file
diff --git a/main.go b/main.go
index 46f9410..a795cbc 100644
--- a/main.go
+++ b/main.go
@@ -20,6 +20,7 @@ import (
 	"aoc2016/day18"
 	"aoc2016/day19"
 	"aoc2016/day20"
+	"aoc2016/day23"
 	"flag"
 	"fmt"
 	"os"
@@ -59,7 +60,7 @@ func initDayFunctions() {
 		20: {1: day20.Part1, 2: day20.Part2},
 		//		21: {1: day21.Part1, 2: day21.Part2},
 		//		22: {1: day22.Part1, 2: day22.Part2},
-		//		23: {1: day23.Part1, 2: day23.Part2},
+		23: {1: day23.Part1, 2: day23.Part2},
 		//		24: {1: day24.Part1, 2: day24.Part2},
 		//		25: {1: day25.Part1, 2: day25.Part2},
 	}