A novel approach was developed to study the non-isothermal crystallization kinetics of polymers based on the Ozawa equation. The method determines the Avrami exponent, n, using exclusively the data confined to the primary crystallization regime. It was applied to a selection of eleven semicrystalline polymers including some biodegradable polyesters. The differential scanning calorimetry exotherms were obtained from the cooling rates covering 2 to 40 K min(-1). As noted, poly(-caprolactone) and nylon 6,10 resulted in the lowest and highest n, being equal to 1.5 and 5.1, respectively. The present findings on n were compared with those reported in the Literature. Their morphological implications were also discussed.