This research work examined the effects of entrepreneurial skill on product portfolio development of medium scale enterprise in Lagos. It is important for business owners (be it a small medium scale enterprises operator or large scale enterprise), who aspire for optimum success in their endeavour to take cognisance of the essential entrepreneurial skills which will aid the effective achievement of their organization goal and objective. The research design adopted for the study is survey research design. The main instrument used was self administered questionnaires. The data obtained from the questionnaires were analysed using mean, median mode and standard deviation. Two hypotheses were tested using Z-test at 0.05% level of significance. The analysis done reveal that there is significant relationship between entrepreneurship skills and product portfolio development. Also, co-operation between small medium scale entrepreneurs and research institutes, for exploitation of research findings of these institutes should be encouraged in order to achieve development in general was recommended.