Abstract: This study has attempted to determine the farmers’ knowledge of identifying insect pests and diseases, as well as perceived contribution of different sources of information enhancing farmers’ knowledge. Two-stage cluster sampling was applied to select 150 cotton growers of district Hyderabad, Sindh, Pakistan in 1999-2000. It was concluded that the farmers’ average score of identifying insect pests in cotton was 46.0% and diseases in cotton was 22.5%. The most important finding of the study was that pesticide Agents’ performance was better than Agricultural Extension Agents performance regarding letting the farmers’ solve insect and disease problem in cotton. Besides, the sources that significantly contributed to enhancing farmers’ knowledge regarding identifying: (1) Insect Pests were Farmers’ Age, help from Pesticide Agents, Discussing with other Farmers’, Watching Agri. Programs on T.V, and Reading Agri. Literature; and (2) Disease were Farmers’ Age, Help from Pesticide Agents and Watching Agri. Programs on T.V. This study will help extension services improve contact system with farmers’ through the use of different sources of information such as T.V, literature and personal visits as these sources were found to have significant impact on farmers’ knowledge.