This paper discusses the present status and future possibilities of blue-green laser technology. Laser developments that are potentially most useful for ocean optics are emphasized. Historically, argon ion lasers have been used for virtually all underwater experiments requiring coherent cw sources, while frequency doubled Nd: YAG lasers have provided pulsed blue-green radiation. Neither of these lasers is appropriate for high-average-power field use. The best present candidate for appli-cations where high pulse energy is of primary importance is the flashlamp pumped dye laser. For range-gated applications, where 5-20 nsec pulses are needed, the copper vapor laser is the best immediate choice. A single pulsed laser that is suitable for both applications is not yet available. A cw laser with reasonable efficiency is also unavailable. With recent UV/visible molecular gas laser developments, it is likely that a single blue-green source capable of satisfying most ocean optics needs will be available within three to five years. Promising possibilities include KrF laser and XeF laser pumping of a blue-green dye laser and Raman downshifting of XeF laser output. Several longer term possibilities for in-band blue-green molecular gas lasers have been identified.