In cases with severe hyperparathyroidism, anaemia improves after parathyroidectomy. The objective of this study was to investigate the influence of treatment with intravenous calcitriol on anaemia in 28 haemodialysis patients. The patients showed moderate to severe hyperparathyroidism (mean parathyroid hormone level 811.6 ± 327 pg/ml) and were treated with calcitriol (2 µg i.v.) after haemodialysis. The follow-up period was 12 months. 21 out of the 28 patients had been receiving erythropoietin (EPO) prior to calcitriol administration; the remaining 7 did not receive EPO. 24 patients received oral or intravenous iron. The doses of EPO and iron were modified throughout the study period to maintain a haematocrit equal to or higher than 30% and ferritin levels above 150 ng/ml, respectively. EPO needs were evaluated according to the relation EPO dose/haematocrit. We found a significant rise in haematocrit and haemoglobin at 3 and 12 months on calcitriol therapy, with no modification of the EPO dose nor ferritin levels. This improvement in anaemia was observed both in those patients who received EPO initially (p < 0.01) and in those who did not (p < 0.05). Upon dividing the patients according to the response of hyperparathyroidism to the intravenous calcitriol treatment, we observed in the responding patients (n = 19) significant increases in haematocrit (from 31.7 ± 4.2 to 36.3 ± 4.9%) and haemoglobin (from 10.6 ± 1.5 to 12.2 ± 1.5 g/dl; p < 0.001) at 12 months on intravenous calcitriol therapy, while this was not true of the non-responding patients. The EPO needs diminished in the group of responding patients and increased in the non-responders, although these changes were not statistically significant. We found no direct correlation between the decrease of parathyroid hormone and EPO needs in the group of responding patients. However, an inverse correlation between parathyroid hormone levels and EPO needs (r = –0.799, p < 0.05) was seen in the group of non-responding patients. Treatment with intravenous calcitriol in patients on haemodialysis controls secondary hyperparathyroidism, improves anaemia, and decreases the need for EPO. Studies including a larger number of patients are necessary to clarify the mechanisms underlying the improvement of anaemia upon control of secondary hyperparathyroidism with intravenous calcitriol treatment and to confirm our findings.