Waste brewery yeast has been used for biosorption of lead and nickel. The dried, ground andrnprotonated yeast has been contacted with Lead (II) and Nickel (II) solutions so as to investigaternimpact of PH, Contact time, presence of co-ion, and study equilibrium and kinetics of thernsorption process. PH has been found to affect lead sorption considerably in the test range of 3rnto 6 where the optimum sorption capacity was found to be PH of 3 to 4. Nickel sorptionrnremained almost unaffected in the PH range 3-7. The higher proportion of the heavy metal ionrnhas been sorbed during 5 to 10 minutes of contacting and equilibrium has been reached withinrn60 minutes where the optimum sorption time is 30min.rnLangmuir and Freundlich adsorption models have been used in the equilibrium study in orderrnto fit the equilibrium data procured after 24 hours of contacting. As to the Langmuir isothermrnmodel, maximum adsorption capacity qmax and affinity,b were found to be 312.5 mg/g andrn0.237 for lead and 526.3 mg/g and 0.005 for nickel respectively. For Freundlich model Kf and nrnhave been determined to be 0.946 and 0.971 for lead and 0.239 and 1.133 for nickelrnrespectively.rnConcerning the kinetics of the metal uptake process, rate of metal uptake has been determinedrnfor varying metal dose in the range of 10-200mg/l and yeast dose in the range of 0.5 â€“ 4 g/l. therncurve fitted better to freundlich model than Langmuir model. The equilibrium uptake capacityrn(qe) rate constant(k) and initial rate of uptake(h) were calculated for metal doses ranging fromrn10- 200 mg/l and yeast biomass dose of 0.5-4 g/l. qe shows an increasing trend for increasingrnmetals dose and is inversely related to yeast dose, similarly, K and h also show increasing trendrnfor metal dose.rnAs to the co-ion tests conducted sorption of lead decreased from 576mg/g to 444.5mg/g whenrnnickel concentration was increased from 50 mg/l to 700 mg/l. But to the contrary increasingrndose of lead did not affect the sorption of nickel. Based on recovery tests, he recoverability ofrnlead (80%) was significantly higher than that of nickel (38%).