Autocrine motility factor receptor (AMFR) is a cell surface glycoprotein of 78000 molecular weight (gp78), regulating cell motility signaling in vitro and metastasis in vivo. To test whether AMFR could be a common mediator of transformation and oncogenic itself, we transfected NIH3T3 fibroblast cells with expression vectors carrying the full-length cDNA for mouse AMFR and evaluated the effects of increased AMFR on transforming potential. The cells stably expressing high levels of AMFR as a result of transfection displayed a complete morphological change and acquired the ability to grow even in low serum. Furthermore, they were anchorage-independent for growth in soft agar and more motile in phagokinetic track assay. Interestingly, the enhanced expression of AMFR produced tumors in nude mice. Our findings provide a direct evidence that overexpression of the AMFR is associated with the acquisition of a transformation phenotype.