The aim of study was to evaluate bone mineral density (BMD) in lumbar spine (AP Spine), total body (Total Body) and distal site of radius (Forearm), and selected markers of bone formation: serum alkaline phosphatase (ALP) and osteocalcin(OC), and bone resorption: pyridinoline (PIR) and deoxy-pyridinoline (DPIR) in urine, in patients with long-standing insulin-dependent diabetes mellitus (IDDM), in comparison to healthy controls. Additionally, the influence of age, sex, smoking, duration of IDDM, the degree of metabolic control, or coexisting chronic complications of diabetes (retinopathy, incipient nephropathy, polyneuropathy) on the studied indices of bone metabolism in patients with IDDM were evaluated. The study was carried on 54 diabetic patients (23 F, 31 M) and 25 healthy individuals (13 F, 12 M). BMD was measured by DEXA (LUNAR DPX-L System). ALP was assessed by enzymatic method, and OC by RIA (Incstar Corporation). PIR and DPIR were assessed by EIA (Metra Biosystems). It was found that patients with long-standing IDDM have significantly lower BMD than healthy controls. The incidence rate of osteopenia and osteoporosis is significantly higher in this group of patients in comparison to the controls. In comparison to healthy subjects, patients with IDDM have significantly higher, but within normal reference range, serum ALP and OC, accompanied by similar PIR and not significantly increased DPIR. Duration and metabolic control of diabetes, or the coexistence of its chronic complications do not correlate with BMD or the studied indicies of bone turnover.