Data were obtained using 75 female rats divided into control, fresh water, and salt water groups. The drug overdose was considered the control because there was no surfactant involvement. Once dead, five animals from each group were autopsied immediately, and the trachea and lungs were removed. Surfactant phospholipids were separated into their component species using high performance thin layer chromatography. Results confirmed the stability of phospholipids during the first 24 hours, with a progressive decrease from 48 hours on until 96 hours. It is concluded that phospholipids represent appropriate biochemical substances for use in studies of forensic interest and that death by drowning, both in fresh and salt water, does not seem to significantly affect their postmortem stability or degradation rate. 16 references and 4 tables