The study portrayed the impact of Agricultural credit Guarantee scheme fund (ACGSF) on Agricultural Sector Development in Nigeria. Specific objectives were to ascertain the relationship between the ACGSF and the output of the crop sector in Nigeria, to examine the relationship between ACGSF and the output of the livestock sector in Nigeria, and to determine the relationship between ACGSF and the output of the fishery sector in Nigeria measured by respective gross domestic product (GDP). Secondary data were sourced from Central Bank of Nigeria Publications and Statistical Bulletin. Multiple linear regression of ordinary least square (OLS) model was adopted to establish the relationship between dependent and independent variables. Findings revealed a positive and significant relationship between ACGSF and the agricultural sector development evaluated by the sustained rise in its contribution to GDP. The study also revealed that the scheme had given more funds and impacted more on the crop sector over the livestock and fishery sector. The study recommends among others that the scheme should be sustained and the government should invest more in Agricultural development, and measures should be put in place by the management of the scheme to reduce default in payment arising from borrowers. Key Words: Agricultural Credit Guarantee Scheme, Gross Domestic Product, Livestock, Fishery, Crop Production.