A study of void initiation was performed on low- and medium-carbon spheroidized steels deformed uniaxially in tension. Voids nucleate preferentially at the interfaces of large cementite particles located on ferrite grain boundaries. The voids elongate in the tensile direction without appreciable growth in the lateral directions. The void-profusion strain is about 0. 8 for 0. 17%C steels and 1. 15 for 0. 44%C steels. The rate of nucleation with deformation was determined.