Farmers' perceptions of Extension services and Extension agents representing agricultural organizations in Antioquia, Columbia, were studied. A total of 370 interviews were made with clients of three Extension Services. A positive correlation was found between the client's perception of the agent and years of schooling, economic status, practices learned and used, and level of contact with the agent. However, the perception of the Extension Services was not associated with the years of schooling, economic status, or level of contact. Only the number of practices used by the client was associated with favorable perception. The most favorable perception was of the Coffee Growers Federation, the oldest organization; the least favorable perception was of the Columbian Agricultural Institute, the newest service. (RS)