Alkaline phosphatase (ALP) is present in human preadipocytes. The aim of this study was to determine the relationship between anthropometry and serum levels of ALP isoenzymes, liver enzymes, albumin, and bilirubin. Anthropometric variables; serum total, bone, liver, and intestinal ALP levels; and alanine aminotransferase (ALT), albumin, total protein, total bilirubin, and g-glutamyltransferase serum levels were measured in 100 volunteers. The levels (given as median [interquartile range]) for total (74.0 U/L [30.0 U/L] vs 62.0 U/L [22.0 U/L]; P <.05) and liver ALP (37.3 U/L [14.6 U/L] vs 26.1 U/L [12.0 U/L]; P < .05) were higher in obese than in lean subjects. The levels of the other ALP isoenzymes and blood analytes were not significantly different between these groups. Albumin and ALT were the only blood proteins studied with serum levels that correlated significantly with waist circumference. This present study demonstrates a relationship between abdominal obesity and serum ALT levels and between body mass index and ALP levels. These findings suggest that serum ALP, particularly liver ALP, is derived from adipose and hepatic tissue.