Weekly urine specimens from 51 long-term catheterized patients yielded 699 isolates of Providencia stuartii. Urease-positive strains represented 23.7% (166) of the isolates, sucrose-positive strains represented 24.5% (171), and lactose-utilizing strains represented 0.7% (5). Urease and sucrose traits were transferred by conjugation to Escherichia coli via an 82-kilobase plasmid; lactose fermentation was transferred by a 150-kilobase plasmid.