Cream together butter, white sugar and brown sugar in a medium bowl.

Beat eggs, then add slowly to creamed butter and sugars.

Add vanilla and combine.

Sift flour, baking soda, salt, and cinnamon; add to creamed sugar mixture and combine well.

Add oats and stir well.

Chill covered dough for approximately 1 hour.

Preheat oven to 375 degrees, roll cookie dough into balls and place 2" apart on greased cookie sheets.

Using a fork dipped in sugar, flatten each cookie.

Bake for 8-10 minutes. Allow cookies to cool on baking sheet for 5 minutes and then remove to wire rack.