The main goal of this study is to estimate the effect of research and development (R D) on the economic growth of Iran , applying three different R D criteria. In addition to R D, labor and capital are used in a Cobb-Douglas production function. Applying a constant return production function and a time series yearly data from 1963 to 2002 the labor productivity is estimated. Using Almon's and the OLS methods, the results show that all three criteria are effective on the economic growth both in the short and long runs. Among the criteria, the effect of R D government spending on economic growth demolishes after three years where the effects of high skilled labor and spending on education vanish after four and two years, respectively.
