This paper describes the measurement of induction time in the reaction crystallization of silver nanoparticles at different temperatures and supersaturations, and compares it with classical nucleation theory. Silver nanoparticles are synthesized by a reaction of silver nitrate with hydrazine in the presence of sodium citrate as stabilizer. Induction time is estimated from an absorption-time graph obtained by monitoring the absorption of the solution after creation of supersaturation. The results show that induction time decreases with increasing supersaturation and temperature. The classical nucleation theory can well predict experimental data. Interfacial tension is estimated at different temperatures and compared with two correlations for calculation of interfacial tension.