Mean platelet volume (MPV) was studied in subclinical hypothyroidism (SH) and the results are conflicting. The aim of this study is to assess how MPV is affected in overt hypothyroidism (OH) and mild SH, the 2 end points of hypothyroidism, in patients having low cardiac risk. Premenopausal women without any cardiac risk, 18 with OH, 30 with mild SH, and 37 euthyroid controls were enrolled. Overt hypothyroidism group had higher low-density lipoprotein cholesterol (LDL-C) and total cholesterol levels than the control group (P < .001 and P < .05, respectively). Increase in MPV was insignificant in OH group when compared with SH and control groups. No correlation was observed between MPV and metabolic and hormonal parameters. Both OH and SH did not influence MPV and high-sensitivity C-reactive protein (hs-CRP) in patients with low cardiovascular risk, but these findings need to be further evaluated in this patient group.