The prevalence of three major coronary risk factors, hyperlipidaemia, hypertension and cigarette smoking, and the change in lipid fractions were assessed five years after coronary bypass surgery and compared to pre-operation in 353 consecutive patients undergoing elective first time surgery at a single centre. Five years after surgery 309 patients were alive without further cardiac surgery, questionnaire follow-up was available in 291 (94%). Lipid profile measurements were made in 255 (83%) of these five-year survivors and 100 (34%) had a history of hypertension. Five years after surgery, 146 (50%) of the 291 patients thought they had high cholesterol, of whom 92 (63%) were following a diet, 36 (25%) were also taking lipid-lowering drugs and 18 (12%) were taking no measures; 141 (48%) of them did not think they had high cholesterol, and four (2%) did not know. There had been a favourable change in all lipid fractions compared with pre-operation, including total serum cholesterol, particularly in patients taking lipid-lowering drugs. However, total serum cholesterol was above 5.2 mmol/l in 203 (80%) patients and low-density lipoprotein (LDL) cholesterol was above 3.4 mmol/l in 180 (71%). Only 30% of patients taking lipid-lowering drugs had an LDL cholesterol of 3.4 mmol/l or less. Blood pressure was recorded in 257 (83%) of the 309 five-year survivors: 82 (28%) were taking antihypertensive medication; 32 (12%) and 87 (34%) patients had a diastolic blood pressure above 95 mmHg and 90 mmHg, respectively, and 49 (19%) had a systolic blood pressure above 160 mmHg. There were 22 (9%) regular cigarette smokers. Corroboration of non-smoking with exhaled carbon monoxide measurements confirmed an accurate history of non-smoking in nearly all patients.