  We present a review of the field of formaldehyde (H2CO) 6cm masers in the
Galaxy. Previous to our ongoing work, H2CO 6cm masers had been detected in the
Galaxy only toward three regions: NGC7538 IRS1, Sgr B2, and G29.96-0.02.
Current efforts by our group using the Very Large Array, Arecibo, and the Green
Bank Telescope have resulted in the detection of four new H2CO 6cm maser
regions. We discuss the characteristics of the known H2CO masers and the
association of H2CO 6cm masers with very young regions of massive star
formation. We also review the current ideas on the pumping mechanism for H2CO
6cm masers.
