diff --git a/src/hence/assembler.cr b/src/hence/assembler.cr
index 4eceeb7..7645d62 100644
--- a/src/hence/assembler.cr
+++ b/src/hence/assembler.cr
@@ -12,7 +12,7 @@ module Hence
         when Parser::AST::ConstantDeclarationNode
           raise "Constants can't be redefined" if data.constants[node.name]?
 
-          data.constants[node.name] = node.value
+          data.constants[node.name] = Parser::AST::BytesArg.new(node.value.resolve(data))
         when Parser::AST::LabelNode
           raise "Labels can't be redefined" if data.constants[node.name]?
 
diff --git a/src/hence/parser.cr b/src/hence/parser.cr
index 39fed74..ee85e9e 100644
--- a/src/hence/parser.cr
+++ b/src/hence/parser.cr
@@ -213,6 +213,29 @@ module Hence
         end
       end
 
+      class BytesArg < Arg
+        property bytes
+
+        def initialize(@bytes : Bytes)
+        end
+
+        def resolve(_data : Assembler::Data) : Bytes
+          @bytes
+        end
+
+        def resolve_as_number(_data : Assembler::Data) : UInt16
+          if @bytes.size == 1
+            @bytes[0].to_u16
+          else
+            Utils.merge_uint16(@bytes[0], @bytes[1])
+          end
+        end
+
+        def to_s : String
+          "\"#{String.new(@bytes).gsub(/\n/, "\\n")}\""
+        end
+      end
+
       class StringArg < Arg
         property string