The Nigerian agriculture is growing sluggish with low production and productivity. This may be due poor agricultural and advisory service in the country. An overview of public and private agricultural extension service in promoting agricultural production and productivity for Nigerian economic growth is offered in this study. Major factors of agricultural extension were recognized and described in this paper. Major constraints to effective extension service delivery in improving agricultural productivity and production were discussed. Absent of legislative policy, weak funding and diversification, low level of private sector participation, low knowledge of extension personnel and weak capacity of extension organization were the major problem to agricultural extension in Nigeria. This study concluded that lack of legislative policy and poor funding were the major constraints to extension agricultural extension service. the study recommended that the challenges identified in the study should be given priority while implementing the agricultural extension policy.

Keywords : Private and public extension, extension delivery, constraints, Nigeria