Culture media selective for Agrobacterium were inoculated with dilutions of soil and crown gall tumor suspensions. Colonies on the selective media were replica plated on a medium with octopine or nopaline. More than 500 isolates were recovered, about 10% of which were confirmed as octopine-utilizing, fluorescent pseudomonads. These strains, together with four other strains of Pseudomonas that had been isolated in a previous study, were characterized for species identity, for utilization of various carbon sources, and for capacity to grow with various opines and amino acids as the sole carbon and nitrogen source. The capacities for octopine and nopaline utilization were generally dissociated, which is similar to the situation found in Agrobacterium. However, most of the octopine-utilizing strains of Pseudomonas showed markedly different growth kinetics in octopine and octopinic acid, two compounds that, in the Agrobacterium system, have been classified into the same opine family. Generally, poor octopinic acid utilization was not correlated with poor ornithine utilization.