Objectives To investigate serum concentration of procollagen type Icarboxyterminal peptide (PⅠP), type Ⅲ aminopeptide (PⅢP) and type Icollagen telopeptide (ICTP) in essential hypertension (EH). Methods Serum levels of PⅠP, PⅢP and ICTP in 42 EH patients and 30 healthy control were measured by radioimmunoassays. Results In EH patients,serum concentration of PⅠP, PⅢP was significantly higher than that in 30 healthy control. Although EH patients did tend to exhibit a higher serum ICTP concentration than normal control subjects, the difference was not statistically significant. EH patients with left ventricular hypertrophy exhibited higher values of PⅠP (P ＜ 0. 05 )and lower values of ICTP (P ＜ 0.05) than EH patients without left ventricular hypertrophy. No significant difference was noted between the serum PⅢP of the EH patients with and without left ventricular hypertrophy (P ＞0.05). Conclusions The results suggest that PⅠP and P Ⅲ P are sensitive serum markers of myocardial collagen synthesis. Myocardial fibrosis may be due to the excessive synthesis and insufficient degradation of collagen. PⅠP, PⅢP and ICTP may be indirect markers of myocardial fibrosis.