Mean platelet volume (MPV) is a determinant of platelet activation. Atherogenic index of plasma (AIP), which is defined as the logarithm of the ratio of plasma level of triglycerides to the level of high-density lipoprotein (HDL)-cholesterol (log[TG/HDL-C]), has recently been used as a marker of atherogenicity. This study included 104 normotensive individuals. Mean platelet volume and AIP were measured in all patients. Nondipper individuals (8.6 +/- 0.9 fL, 0.3 +/- 0.2) demonstrated higher values of MPV and AIP compared with dippers (7.9 +/- 1.1 fL, 0.1 +/- 0.2) (P<.001 and <.001, respectively). Mean platelet volume and AIP have a positive correlation with insufficient decline in nocturnal blood pressure.