The goal of any medicolegal investigation of human victims found in water is the identification of the victim, the evaluation of postmortem (PM) submersion time, and the determination of the cause and manner of death. Many factors must be considered in such an investigation, including environmental factors and the victim’s preexisting condition. Since factors other than drowning must be taken into account as the cause of death, the interpretation of autopsy findings requires a sound knowledge of the pathophysiology of drowning. Morphological changes associated with drowning include those related to liquid penetration into the airways, such as frothy liquid present in the airways or the presence of external foam. Laboratory methods for diagnosing drowning are based on the shift of liquid and electrolytes across the pulmonary air-blood barrier, although it should be noted that the usefulness of such methods is hampered by factors such as postmortem biochemical instability. The diatoms method for the diagnosis of drowning is described but the authors warn that until standardized protocols and reliable separation values for diatoms are established, this method cannot be used for the definitively diagnosis of drowning. Figures, references