Background To gain insight into the prevalence of and trends in plasma cholesterol levels in the general population of the Netherlands, a monitoring project was carried out from 1987 to 1992. Methods Each year a random sample of men and women aged 20–59 years in three towns in the Netherlands was invited to participate in the study. The overall response rate was 50% for men and 57% for women and a total of almost 42 000 men and women participated. Total (TC) and high density lipoprotein cholesterol (HDL-C) was measured and the non-HDL-C/HDL-C ratio was computed. Data were age-standardized to the Dutch population distribution aged 20–59 years. Results The prevalence of hypercholesterolaemia (TC >605 mmol/l) in men ranged from 5% in the youngest (20–29 years) to 29% in the oldest age group (50–59 years), and from 4% to 38% in women Low HDL-C levels (≤0.9 mmol/l) in men ranged from 15% in the youngest to 26% in the oldest age group, and in women from 4% in the youngest to 7% in the oldest age group. The lipid profile of those with a higher educational level was more favourable than that of the less educated. From 1987 to 1992, in men, TC decreased by 0.12 mmol/l, HDL-C decreased by 0.07 mmol/l and the non-HDL-C/HDL-C ratio increased by 0.22. In women no statistically significant changes were observed. Changes over time did not differ according to age and educational level. Conclusions The prevalence of hypercholesterolaemla is still high in the Netherlands During the period 1987–1992 the lipid profile worsened in men and remained stable in women.