SummaryIt is currently recommended to administer a maintenance dose of 100 μg of venom at 4–6 week intervals for Hymenoptera venom immunotherapy (VIT), Because the optimal duration of therapy is not known, we decided to progressively prolong the interval between maintenance injections instead of accepting the risk of anaphylactic reactions when VIT is discontinued after a predetermined period. We report here on the results of a first phase of this interval extension programme, covering the gradual increase of the interval from 1‐12 weeks over 19 months in 178 patients. A 12‐week interval maintenance VIT could be achieved in 117/128 (91%) of yellow jacket venom (YJV) and in 35/50(70%) of honeybee venom (HBV) allergic patients. At the lime of the interview these 152 patients had been treated with 12‐weekly 100 μg venom injections for an average period of 2 years without any untoward reaction to VIT. During this period of 48 YJV allergy sufferers experienced 77 field re‐stings without systemic reaction (SR), and 17 HBV allergic subjects were restung at least 213 times in total, with one patient developing a very large local reaction and one a mild systemic reaction. In 26 of the 17S patients the interval of 12 weeks was not reached for various reasons, with a higher failure rate among the HBV allergic patients. Most Hymenoptera venom allergic patients can thus be safely and effectively treated with 12‐weekly injections of