In the pea straight growth bioassay, both benazolin and indole-3-acetic acid (auxin) solutions promoted the elongation of etiolated pea (Pisum sativum L. ‘Alaska’) epicotyls. Maximal elongation occurred at auxin concentrations ranging from 10-6 to 10-4 M; comparable elongation occurred at a benazolin concentration of 10-4 M. Results of this bioassay indicate that benazolin functions as an auxin, but is much less active than naturally occurring indole-3-acetic acid.