In this study long run relationship between agricultural research and TFP (total factor productivity) is estimated by using Cointegration technique for 1970-2005. The results of the long run relationship between TFP and agricultural research indicate that agricultural research has a significant and positive impact on TFP. The estimated coefficient of research is 0.571 and it is significant at 1 percent level of significance. Granger-causality tests show a bidirectional relationship between research and productivity. The estimate of marginal internal rate of return (MIRR) to research is found to be 73 percent, indicating that Punjab agricultural research system remained productive.