This study was designed to determine the nature and intensity of farmers' participation in Integrated Agricultural Development Projects (IADP) in Peninsular Malaysia. Specifically, the objectives of the study were to: (1) determine the demographic characteristics of the farmers in IADPs, (2) assess farmers' knowledge of IADP, (3) determine farmers' attitudes toward IADP programs, (4) determine farmers' attitudes toward IADP personnel, (5) assess the nature and intensity of farmers' participation in developmental activities in IADP, (6) determine the differences in selected variables among IADPs, and (7) assess the relationships between selected variables and intensity of participation;Data for the study were solicited from 200 farmers through personal interviews using a pre-coded questionnaire. The farmers were randomly selected from four IADPs: North West Selangor, Krian Sungai Manik, West Johore, and West Pahang projects. Reliability, frequencies, analyses of variance, product-moment correlation, and multiple regression analyses were employed to analyze the data;Farmers' intensity of participation in IADP was measured by a composite score derived from: (1) participation in decision making, (2) participation in implementation, (3) participation in benefits, and (4) participation in evaluation;Findings of the study revealed: (1) low participation by farmers in IADPs; (2) significant differences in land ownership, agricultural income, total income, composite knowledge score, attitudes toward IADP programs, attitudes toward IADP personnel, and intensity of participation; (3) significant relationships were observed between intensity of participation in IADP and the following variables: formal education, land ownership, agricultural income, composite knowledge score, attitudes toward IADP programs, and attitudes toward IADP personnel; (4) six independent variables were found to have significant relationships with intensity of participation. However, only five variables were included in the proposed prediction equation of estimating farmers' intensity of participation. The variables were: farmers' composite IADP knowledge score, farmers' attitudes toward IADP programs, rice as main crop, farmers' attitude towards IADP personnel, and gender.