Heavy metal pollution in the water supply is a serious environmental problem that affects human health around the world. The goal of this study was to investigate the adsorption behaviour of sugarcane bagasse (SB) and corn stalk (CS) biomass for Pb(II) and Cd(II) removal from metal-contaminated water. When the doses of biomass were increased in solutions containing Pb(II) and Cd(II), the SB and CS showed a trend of increasing metal removal efficiency. The removal efficiency of biomass for Pb(II) decreased as the pH of the solution increased from 5.0 to 7.0, with an optimum pH range of 5 to 6. However, pH has little influence on the removal efficiency of biomass for Cd(II). Adsorption equilibrium is reached in about 15 min. Adsorption for at least four cycles improves Pb(II) removal efficiency (up to 98 %) in solutions containing only Pb(II). The best fitness of the adsorption isotherm to Freundlich suggests multilayer adsorption of metal ions onto CS. Higher qmax and Kf suggest that SB and CS have a greater affinity for Pb(II) than for Cd(II). Pb(II) adsorption potential was found in biomass derived from SB and CS, but it was less effective as a Cd(II) adsorbent. For application in environmental clean-up, we suggest further study on the structural modification of biomass to enhance its metal removal capacity, the regeneration of biomass for better results, and field trials for practical application. HIGHLIGHTS The adsorption behaviour of sugarcane bagasse and corn stalk biomass for Pb(II) and Cd(II) removal from metal-contaminated water was studied The removal efficiency of Pb(II) increases with increased doses of biomass and decreases with increased solution pH and metal initial concentrations Adsorption for at least four cycles improves metal removal efficiency in the case of Pb(II) Freundlich’s isotherm suggests multilayer adsorption of Pb(II) and Cd(II) onto corn stalk biomass Higher qmax and Kf values suggest that sugarcane bagasse and corn stalk have a higher affinity for Pb(II) than Cd(II)