diff --git a/2020/README.md b/2020/README.md
index 24f21f2..f75ce6c 100644
--- a/2020/README.md
+++ b/2020/README.md
@@ -185,3 +185,17 @@ Inside after changes:
 ### Time
 
 `bash -c 'time sbcl --script day08.lisp'`
+
+## Day 09 - Chapel
+
+### Build
+
+`chpl -o day09 day09.chpl`
+
+### Run
+
+`./day09`
+
+### Time
+
+`bash -c 'time ./day09'`
diff --git a/2020/day09/.gitignore b/2020/day09/.gitignore
new file mode 100644
index 0000000..768f546
--- /dev/null
+++ b/2020/day09/.gitignore
@@ -0,0 +1 @@
+day09
diff --git a/2020/day09/build.sh b/2020/day09/build.sh
new file mode 100755
index 0000000..449bb07
--- /dev/null
+++ b/2020/day09/build.sh
@@ -0,0 +1 @@
+chpl -o day09 day09.chpl
diff --git a/2020/day09/day09.chpl b/2020/day09/day09.chpl
new file mode 100644
index 0000000..217ecd3
--- /dev/null
+++ b/2020/day09/day09.chpl
@@ -0,0 +1,80 @@
+// TODO change list to array?
+// TODO make it parallel? using forall
+
+module Day09 {
+  private use IO;
+  private use List;
+
+  config const sample: bool = false;
+  const fileName: string = if sample then "sample.txt" else "input.txt";
+  const preambleSize: int = if sample then 5 else 25;
+
+  proc main() throws {
+    const input: list(int) = readInput(fileName);
+
+    writeln("Solving Day09A...");
+    // 15353384
+    const resultA = solveA(input);
+    writeln(resultA);
+
+    writeln("Solving Day09B...");
+    // 2466556
+    const resultB = solveB(input, resultA);
+    writeln(resultB);
+  }
+
+  proc solveA(input: list(int)): int {
+    var result$: single int;
+    forall i in preambleSize .. input.size-1 {
+      const current = input[i];
+      const preamble: domain(int) = input[i-preambleSize .. #preambleSize];
+      //writeln(preamble);
+      //writeln("i ", i, " ", input[i]);
+      var valid: bool = false;
+      for p in preamble {
+        //writeln("p ", p);
+        if preamble.contains(current - p) && 2*p != current {
+          valid = true;
+          break;
+        }
+      }
+      if !valid {
+        result$ = current;
+      }
+    }
+    return result$;
+  }
+
+  proc solveB(input: list(int), n: int): int {
+    var result$: single int;
+    forall i in 0 .. #(input.size - 1) {
+      //writeln(i, " ", input[i]);
+      var currNum: int = input[i];
+      var contSum: int = currNum;
+      var contSumList: list(int);
+      contSumList.append(currNum);
+      for sumIndex in i+1 .. input.size-1 {
+        if contSum >= n then break;
+        currNum = input[sumIndex];
+        contSum += currNum;
+        contSumList.append(currNum);
+      }
+      //writeln(contSumList);
+      if contSum == n && contSumList.size >= 2 {
+        contSumList.sort();
+        result$ = contSumList.first() + contSumList.last();
+      }
+    }
+    return result$;
+  }
+
+  proc readInput(fname: string): list(int) throws {
+    var input: list(int, parSafe=true);
+    var f = open(fname, iomode.r);
+    for line in f.lines() {
+      input.append(line:int);
+    }
+    f.close();
+    return input;
+  }
+}
diff --git a/2020/day09/sample.txt b/2020/day09/sample.txt
new file mode 100644
index 0000000..28d66e4
--- /dev/null
+++ b/2020/day09/sample.txt
@@ -0,0 +1,20 @@
+35
+20
+15
+25
+47
+40
+62
+55
+65
+95
+102
+117
+150
+182
+127
+219
+299
+277
+309
+576