This paper discusses critical input and output factors of R&D in higher education institutions in Nigeria. It also shows quantitative analyses of researchers' productivity using partial productivity approach and an assessment of factors influencing research productivity. Based on a recent research effort, researchers were sampled from 12 leading universities. They were randomly selected from the fields of agriculture, science and technology/engineering. Findings from the results reveal that productivity of the researchers is of medium category. Also, input factors such as qualifications of researchers, years of experience, research collaborations and time spent on research significantly contribute to research productivity.