We introduced mated European honey bee (Apis mellifera L.) queens into Africanized and European colonies during three different seasons to determine if there were differences in acceptance rates. We also sampled volatile compounds emitted by the queens prior to their introduction to determine if amounts of certain compounds were related to acceptance rates. More queens were accepted by European colonies compared with Africanized both in the first week after introduction and during the 6-week observation period. Africanized colonies rejected the most queens in the first week during the spring introductions and had the highest supersedure rate during introductions made in the summer. Queens that were rejected during the first week after introduction had lower amounts of E-B-ocimene than those that were accepted for the 6 week period. E-B-ocimene was the only consistently detected compound in queens prior to their introduction, and it did not differ in amounts among the seasons indicating that threshold amounts of the compound for queen acceptance might differ with season and colony condition. The best time to introduce European queens into colonies appears to be in the fall when overall rejection rates are the lowest.