Aim: Evaluate the roles of water temperature and submersion duration in the outcome of drowning victims. Methods: Subjects were those who drowned in open water (lakes, rivers, and ocean) in three counties in Washington State between 1975 and 1996. We performed a case control study to assess the association between age, reported submersion duration, and estimated water temperature and drowning outcomes. Cases were victims with good outcomes (survival with normal or mild/moderate neurologic sequelae). Controls were victims with bad outcomes (death or severe neurologic sequelae or persistent vegetative state). We used Poisson regression to estimate odds ratios (OR) and 95% confidence intervals (CI). Results: Of the total 1094 open water drowning victims, most were male (85%),white (84%), and with a mean age of 27 years. Most drownings occurred in lakes (51%) and in cold (≥6-16 °C (44%)) or very cold waters (<6 °C (34%)). Most (78%) had bad outcomes (74% died; 4% survived with severe neurologic sequelae. Of those with good outcomes, 88.2% were submerged <6 min, 7.4% 6-10 min and 4.3% for 11-60 min. Victims with good outcomes were 61% (95% CI 0.23-0.65) less likely to be submerged for 6 to 10 min and 98% (95% CI 0.01-0.04) less likely to be submerged for 11 or more minutes. Water temperature was not associated with outcome. Conclusions: A protective effect of cold water for drowning victims was not found; estimated submersion duration was the most powerful predictor of outcome. Recommendations for initiation of rescue and resuscitation efforts should be revised to reflect the very low likelihood of good outcome following submersion greater than 10 min.