Survival of Vibrio parahaemolyticus in various diluents was investigated. 100 mM potassium phosphate buffers (pH 6, 7, and 8) without added NaCl were extremely deleterious to V. parahaemolyticus 04:Kll in comparison to the same diluent with either 0.5, 3, or 6% NaCl. Maximum counts were obtained when phosphate buffers containing 3% NaCl were used as diluents. There were no significant differences among survivor counts of cells exposed for 20 min to 100 mM potassium phosphate 3% NaCl buffer at either pH 6, 7, or 8. Greater than 99.9% of the cell population was destroyed within 20 min in 0.1% peptone diluent without NaCl when compared to 0.1% peptone with either 0, 5, 3, or 6% NaCl. Cell counts using 0.1% peptone diluents containing 3 and 6% NaCl were not significantly different; however, both were superior to 0.1% peptone containing 0.5% NaCl. Survival data for V. parahaemolyticus 04: Kll in distilled water containing 0, 0.5, 3. and 6% added salt were similar to data for the 0.1% peptone diluents. Culture age (4, 10, and 24 h) and time of exposure to the diluents also significantly affected survival of V. parahaemolyticus 04:Kll and 17802.