Severe hyperparathyroidism(i-PTH>1,000pg/ml, dia-meter of nodules>1.0cm, and hypercalcemia) in dialysis patients may be resistant to conventional calcitriol- pulse therapy. To assess the usefulness of direct calcitriol injections in restoring the responsiveness to calcitriol, we performed a prospective study in 23 dialysis patients(mean age 42.3 years, M: F 0.9: 1, CGN 14, hypertension 4, lupus nephritis 2 & others 3, mean duration of dialysis 9.5 years, HD: CAPD 9: 14) who had severe hyperparathyroidism resistant to calcitriol pulse therapy for more than 2 months and had no ectopic gland in Sestamibi parathyroid scan. We three repeatedly injected calcitriol of dose(Mg) equal to 3-D nodule volume(cm3) under U.S.(Acuson Computa Sono, California, USA, 7MHz probe) for 1 week and concurrently began calcitriol-pulse therapy(0.75-1.0Mg/day, t.i.w.) after 3rd injection. All patients were followed up by serum i-FI H(Allegro Intact FPH kits, Nichols Ins.), calcium, phosphate, and U.S. after 7 days, 1 month, 6 months, and 1 year of 3rd calcitriol injection. These combination therapy could significantly decrease i-PTH level and gland volume in patients with resistant secondary hyperparathyroidism on conventional calcitriol therapy and the response were main-tained for one year after start of these therapy. The complete response group was the patients with lower baseline i-FFH levels compared to those with partial and non-response(1001.7+/-150.2 vs. 1521.8+/-328.3, 1569.2 +/-344.3pg/ml, p<0.05, respectively). The patients with baseline i-PTH of less than l,200pg/ml or gland volume of less than 1.5cm were well responded to the three consecutive direct calcitriol injection and pulse combination therapy(i-PTH; PPV 77.8%, NPV 92.8%, gland volume', PPV 87.5%, NPU 93.3%). No severe adverse effect was observed during this study. In conclusion, direct calcitriol injections into the parathyroid nodules and pulse combination therapy could be useful in secondary resistant hyperparathyroidism patients with conventional calcitriol therapy especially in those with i-PTH of less than 1,200pg/ml or gland volume of less than 1.5cm. However, sugical management may be indicated in patients with higher i-PTEI levels or larger gland volume than these.