The protein binding of salicylate analogs has been investigated by equilibrium dialysis. A series of binding experiments were performed in order to elucidate the effects of physicochemical properties of salicylate analogs on the binding with bovine serum albumin. Attempts to correlate affinity constants with capacity factor, steric factor and Hammett ${sigma}$ values suggested hydrophobic forces to be involved in the binding of salicylate analogs. Steric factor contributes to binding process partly, whereas electronic interaction appears to be insignificant.