NAFTA is North American Free Trade Agreement which provides investors with a remarkable set of terms and conditions in order to stimulate direct foreign investment from United States to Canada and Mexico. Since its inception in 1994, the agreement has been appreciated for the benefits U.S. economy reaped through it and criticized for the negative impacts it might have had on U.S. economy. This paper discusses some of the negative and positive impacts of NAFTA on U.S. economy over a period of time with respect to U.S. trade balance, employments, jobs, and wages.