In this study, we describe a green and simple procedure for biosynthesis of ZnO nanoparticles using Candida albicans as eco-friendly reducing and capping agent. The synthesized ZnO nanoparticles were characterized by UV–vis spectroscopy, powder X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL), thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). The prepared nano-particles were used as catalyst for the fast and efficient synthesis of steroidal pyrazolines (4–9) from α, β-unsaturated steroidal ketones (1–3). The target molecules were obtained in good to excellent yields applying the current method.