Combine rhubarb, strawberries and sugar. Place in a 23 cm square baking dish. Combine flour, oats, brown sugar and butter, mixing until crumbly. Sprinkle crumb mixture over rhubarb and strawberries.
Bake in preheated moderate oven (350 degrees) for about 40 minutes or until rhubarb is tender.
NOTE: If fresh strawberries are used, increase sugar to half cup.