SummarySuperBoost® is a proprietary commercial product comprising the non-volatile 10-component honey bee brood pheromone, stabilized with an antioxidant, and delivered to a colony in a controlled release device. The pheromone (180 mg) is contained in a plastic pouch with a pheromone-permeable polyethylene release membrane and a pheromone-impermeable Mylar backing. The pouch is mounted in a solid plastic holder. A 12-replicate, 70-day, single-blind experiment was set up on 4 February 2009 at Abbotsford BC, Canada, to test the utility of SuperBoost for enhancing spring build-up of overwintered honey bee colonies. Colonies were randomly assigned as untreated controls or to be treated with freshly-loaded SuperBoost devices. Devices were replaced once (after 37 days). Supplementary pollen substitute (Bee Pro®) was fed to bees ad libitum. Measurements of BeePro consumption were made on nine occasions. On days 16 and 70 the area of brood comb and numbers of adult bees were determined. When colonies were divided (split), the numbers of daughter colonies were recorded. Two colonies treated with SuperBoost died during the experiment, as did one control colony. SuperBoost devices released 0.37 and 0.54 mg per day of pheromone over the two exposure periods, as determined gravimetrically. By Day 70, treated colonies had consumed 50% more BeePro than control colonies. Treated colonies had significantly more brood comb area (2.4 times) and adults (2.0 times) than control colonies. By day 96, six of the 10 surviving SuperBoost treated colonies had produced nine daughter colonies, a significantly higher proportion than the two of 11 control colonies, which produced four splits. We suggest that SuperBoost has substantial potential for enhancing the spring build-up of overwintered colonies.