Association processes of D-fructose dehydrogenase (FDH) onto surfaces of liposomes which were composed of N-(5-dimethylamino-1-naphthaienesulfonyl)-L-alpha- dimyristoylphosphathanolamide and L-alpha-dimyristoylphosphatidylcholine or L-alpha-dimyristoylphosphatidylglycerol (1:9) were investigated by the fluorescence stopped-now technique. The association processes were divided into two relaxation processes : the faster process whose apparent rate constant monotonously increased with the concentration of FDH, and the slower process whose rate constant showed a saturation behavior. Taking the number of binding sites on the liposome surface into consideration, the corrected association rate constant of the faster process was 4.4% of the theoretical value for a binary collision, probably due to a disadvantageous surface-searching and dehydration processes on the liposome and protein surfaces. The Arrhenius plots of the rate constants both for the faster and slower steps showed a discontinuous change around the gel to liquid-crystal phase transition temperature of the liposomes. Strong influences of deformability of liposomes, and state of hydrating water molecules around polar heads, on the rate of association processes were suggested.