The aggregation behavior of nystatin (NYS) in the presence of pluronic F127, triblock copolymer of poly (ethylene oxide) (PEO) and poly (propylene oxide) (PPO), was measured and correlated with hemolytic activity. Antifungal activity was also studied using Saccharomyces cerevisiae as a model strain. The critical aggregation concentrations (CAC) of the drug were 50.1, 108.0, 134.2, 154.3, and $217.9;{mu}M$ at 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% pluronic F127 solution, respectively. The levels of NYS required to start lysis of erythrocytes were about 80, 100, 125, 150, and $200;{mu}M$ at 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% pluronic F127 solution, respectively. It was $50;{mu}M$ in the absence of the polymer. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of NYS-pluronic F127 lyophilizate were same at $3;{mu}g/ml$, while MIC and MFC of pure NYS are $3;{mu}g/ml$ and $12;{mu}g/ml$, respectively. By modulating the aggregation behavior of NYS, pluronic F127 was able to reduce the toxicity of the drug without compromising the MIC and MFC.