Seventeen serum chemistry analyses were performed on blood collected from captive diamond-backed water snakes. Means, standard deviations, and ranges were calculated for each assay. There was no correlation between the chemistry values and sex or size. The reported values for sodium, potassium, glucose, and total protein fell within the ranges found in the present study, but the values for chloride and blood urea nitrogen were higher, and calcium, bicarbonate, and osmolality were lower. Some snakes had unexpectedly very low serum glucose values which could not be explained by technique or methodology. There was a wide range in enzyme measurements which could be partly due to handling prior to death.