This study intends to investigate the presence and levels of organochlorine pesticides (OCP) in fish, water, and sediment samples obtained from a river in Agbara, Ogun State, and suggest the associated consumption risks. Pesticide residues were extracted using ultrasound sonication and soxhlet extraction, followed by their quantification using gas chromatography with an electron capture detector. Supercritical fluid and liquid/liquid extraction methods were used to clean up the sediment and water samples. Analysis revealed the presence of 23 organochlorine pesticides, including endrin-ketone, endrin-aldehyde, p,p’-DDT, and heptachlor epoxides, with mean concentrations above WHO and FAO maximum residue limits. The water samples contained high levels of contaminants such as endrin-ketone (0.65 mg/L), endrin-aldehyde (0.30 mg/L), p,p’DDT (1.31 mg/L), and heptachlor epoxide (1.15 mg/L). These findings indicate the accumulation of hydrophilic substances in sediments and fatty tissues. While current fish consumption may not pose immediate health risks, long-term accumulation could be hazardous. This study highlights the importance of mitigating organochlorine pesticide contamination and calls for further research and effective pollution control strategies. The findings demonstrate the widespread presence of OCPs in all matrices, with concentrations in water samples notably surpassing permissible limits, highlighting significant environmental and potential health concerns.