Mix together four, baking soda and cinnamon.

Beat together butter, brown sugar and granulated sugar at medium speed until light and fluffy. Beat in egg and vanilla.

At low speed, beat in flour mixture until blended. Fold in oats and chocolate chips. Cover with plastic wrap; chill for 1 hour.

Preheat oven to 350. Grease 2 baking sheets.

Shape dough into 1 inch balls. Place cookies, 2 inches apart, on prepared baking sheets. Flatten each cookie slightly.

Bake cookies until lightly browned around edges, 10 to 12 minutes. Transfer baking sheets to wire racks to cool completely.