Proteinuria was estimated using modified biuret method in 100 consecutive essential hypertensives of both sexes with mean age of 40 +/- 0.9 (18-50 yr) attending hypertension clinic. Proteinuria (mg/1.73 M2/24 h) in 60 mild hypertensives ranged from 45.4 to 493.0 with 9 (15%) patients having abnormal proteinuria (greater than 250 mg). In 26 moderate hypertensives proteinuria ranged from 96-1010; 7 (27%) had abnormal proteinuria. The proteinuria in 14 severe accelerated, malignant hypertensives ranged from 146.5-6132.6 with 10 (71%) having abnormal proteinuria. Duration of hypertension had no correlation with the amount of proteinuria. The amount of proteinuria was much higher (P less than 0.001) in patients with renal insufficiency (1322.5 +/- 586.4) and in patients with grades III and IV hypertensive retinopathy. LVH on ECG also correlated positively with proteinuria. The group with abnormal proteinuria had more patients with LVH (42.3% vs 12.2%), severe hypertensive retinopathy (30.8% vs 4.1%) and renal insufficiency (34.6% vs 0%) as compared to patients without elevated proteinuria.