Kluyveromyces marxianus was grown in submerged culture in a complex medium with several potential inducers of lipolytic activity (triacylglycerols, fatty acids). The highest extracellular lipolytic enzyme production (about 80 U ml(-1) in 3 d) was obtained when the medium was supplemented with 2 g urea l(-1) plus 5 g tributyrin l(-1). Addition of surfactants (1 g l(-1)) did not improve production. The lipase had a high thermal stability in aqueous solution (73% residual activity after 9 d at 50 degreesC, 16 min half-life time at 100 degreesC). It was also stable at acidic pH and showed good tolerance to organic solvents (70% residual activity after 2 d in n-hexane of cyclohexane).