The study of embryonic development in Drosophila melanogaster has contributed major insights into the mechanisms of development, gene regulation and evolution. We have explored the role of heat shock factor (HSF) in regulation of an even-skipped (eve) transgene in Drosophila embryos. The traditional role of HSF is to activate transcription of the heat shock proteins (HSPs) in response to stresses. Previous work had not implicated HSF in regulating non-HSP targets in embryos. Our results demonstrate that HSF is capable of regulating a developmental gene in embryos. This is the first demonstration that HSF is capable of activity in embryos that is not related to environmental stress.