In this study, the adsorption of endosulfan, a type of pesticide, onto agricultural waste-based adsorbents, namely, oil palm shell activated carbon (PSAC) and rice husk ash (RHA), was investigated. The as-received adsorbents were used for batch α- and β-endosulfan adsorption studies which included kinetics and equilibrium aspects at a constant solution pH of 5 and at a temperature of 25ºC. It was found that removal of β-endosulfan by both adsorbents was significantly more efficient than that of α-endosulfan indicating a high affinity of PSAC and RHA towards β-endosulfan. Interestingly, kinetic equilibrium for β-endosulfan adsorption onto PSAC was achieved after 30 min of contact time with a very high capacity of 418 mg g^-1. The adsorption kinetics data fitted the pseudo-second order model well, implying chemisorption was the rate-controlling step. Equilibrium adsorption data for PSAC fit the Freundlich isotherm better than the Langmuir isotherm, suggesting the existence of multi-layer adsorption of endosulfan on a relatively heterogeneous PSAC surface. It was found that PSAC was efficient in removing β-endosulfan from water while it was conversely true for RHA.