Idiopathic hypertriglyceridemia has been reported in Miniature Schnauzers (MS). However, studies investigating the prevalence of this disorder in a large population of MS are lacking. Hypertriglyceridemia is prevalent in healthy MS. This study used 192 healthy MS and 38 healthy dogs of other breeds (control dogs). Serum triglyceride and cholesterol concentrations were measured and statistically compared in both the MS and control group. Dogs were categorized based on their age, and median serum triglyceride concentrations were compared among different age groups. A total of 63 (32.8%) of the 192 MS had serum triglyceride concentrations above the reference range. In contrast, of the 38 control dogs, only 2 (5.3%) had serum triglyceride concentrations above the reference range. The median serum triglyceride concentration in MS was 73.5 mg/dL, which was significantly higher as compared to that of the control group (median, 55 mg/dL; P = .0005). Serum cholesterol concentration was above the reference range in 9 (9.0%) of 100 MS and in 2 (5.3%) of the control dogs. Mean serum cholesterol concentrations were not significantly different between the 2 groups (P = .1374). Median serum triglyceride concentrations in MS increased significantly with age (P < .0001), and there was a significant positive correlation between serum triglyceride concentrations and age (Spearman r = 0.47; P < .0001). There was no difference in serum triglyceride concentrations between male and female MS (P = .48). Healthy MS have a high prevalence of hypertriglyceridemia as compared to healthy dogs of other breeds. Both the prevalence and severity of hypertriglyceridemia increase with age.