A comparison between two quantities concerning quiescent crystallization of polymer melts, namely the quiescent crystallization onset time (t (on,q)) and gel time (t (gel)), is performed using rheological methods. It was found that t (gel) as measured from the evolution of loss angle (tan delta) occurs slightly earlier than t (on,q), defined as the time required for the viscosity to reach twice its steady-state value. The change of viscosity with time was measured with Small Amplitude Oscillatory Shear (SAOS) method. Two alternative methods to measure t (on,q) are studied: by continuous shear at a very small shear rate and by creep method. A very good agreement from all the three methods was achieved, indicating the robust nature of this quantity. Finally, the gel times for different PB-1 samples are considered. When the difference in crossover angular frequencies (omega (x) ) of the samples is taken into account in performing t (gel) experiments, it can be shown that the temperature dependence of t (gel) for the samples are the same. However, for samples having high molecular weight t (gel) measurements are problematic. In this case, t (on,q) serves as an easier tool to compare the crystallization behaviour of different samples.