AbstractThe polycystic ovary syndrome (PCOS) imparts health risks including dyslipidaemia, diabetes and cardiovascular disease that are amenable to lifestyle adjustment and/or medication. We describe dyslipidaemia in women referred to a gynaecological endocrine clinic. Clinical data and endocrine and lipoprotein investigations comprising fasting triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDLC) and calculated low density lipoprotein cholesterol (LDLC) were studied along with electrophoresis patterns of apolipoprotein B‐containing lipoproteins. The 1721 participants comprised black, mixed ancestry, white and Indian individuals (9.8%, 83.2%, 5.8% and 1.2%, respectively). The mean ± standard deviation of the age, body mass index (BMI) and waist/hip ratio were 26.0 ± 5.9 years, 32.3 ± 8.3 kg/m2 and waist/hip ratio 0.88 ± 0.11, respectively. Overweight status (BMI 26–30 kg/m2) and obesity (BMI >30 kg/m2) involved 272 (15.8%) and 1010 (58.7%) individuals, respectively. Morbid obesity (BMI >40 kg/m2) was present in 309 (17.9%) individuals. The TG, TC, HDLC and LDLC concentrations were 1.22 ± 0.86, 4.77 ± 1.02, 1.3 ± 0.36, 2.94 ± 0.94 mmol/L, respectively. LDL hypercholesterolaemia occurred in 753 (43.7%) and exceeded 5 mmol/L in 39 (2.3%) women. Low HDLC (<0.9 mmol/L) affected 122 (7%), hypertriglyceridaemia (>1.7 mmol/L) affected 265 (15.4%) and exceeded 2.5 mmol/L in 91 (5.3%) women. Mixed hyperlipidaemia (TG >1.7, TC >5.0 mmol/L) occurred in 176 (10.2%). Electrophoresis revealed small LDL particles in 79 (4.6%) and dysbetalipoproteinaemia in 13 (0.76%) of the cohort. Small LDL associated with obesity, blood pressure, TG and glucose concentration and higher androgenic state. Many women with PCOS had unfavourable lipoprotein results: mostly moderate changes in TG, HDLC and LDLC. Small LDL is not rare, may aid risk assessment and is best determined directly. Incidental monogenic disorders of lipoprotein metabolism included dysbetalipoproteinaemia, familial hypercholesterolaemia and severe hypertriglyceridaemia. Dyslipidaemia in PCOS requires more careful diagnosis, individualised management and research.