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The development of a rational and efficient control strategy against Asian rust caused by Phakopsora pachyrhizi requires knowledge of the pathogenicity and local variability of the pathogen. The general objective of this study was to phenotypically characterize some isolates of P. pachyrhizi in Cameroon. In five agro-ecological zones (AEZ), 34 isolates of P. pachyrhizi were collected from diseased leaflet samples of soybean taken in the field. The length (L) and width (w) of the phenotypic forms of different uredospores of the isolates obtained were observed and measured under the light microscope. The length to width ratio (L/w) was calculated and the isolates aggressiveness was evaluated. Microscopic observation revealed seven different uredospore shapes including two new ones (seedlike and angular). Uredospore lengths ranged from 25.40 to 27.64 μm; widths from 16.64 to 19.61 μm; and L/w ratio from 1.45 to 1.57. The pathogenicity test on detached leaflets showed that the P. pachyrhizi isolates obtained were pathogenic with varying degrees of aggressiveness at 14 days after inoculation (DAI). The most aggressive isolates were obtained in AEZ II (GA1, WA and MB with aggressiveness of 84; 84.33 and 76.67 % respectively), AEZ III (BAM, 84 %) and AEZ V (MF2, 79.33 %). These morphological characters and different degrees of aggressiveness reveal a great variability of P. pachyrhizi uredospores in Cameroon. [ABSTRACT FROM AUTHOR]