Rotylenchulus reniformis was pathogenic to cantaloup (Cucumis melo 'Perlita') under greenhouse conditions. These findings confirm field symptoms of cantaloup infected with R. reniformis. Histopathological studies show that the nematode penetrates the cortex perpendicular to the vascular system and comes to rest with the head against the endodermis in young roots. Feeding stimulated the pericycle to either side of the endodermal feeding cell and caused cell hypertrophy with enlargement of the nucleoli and granular thickening of the cytoplasm. In older roots where the endodermis had collapsed, the nematode fed directly into the pericycle and caused similar symptoms. Nematode development was more rapid at 27 C than at 21 C.