An L-3-phase is observed for the first time in a ternary phase diagram of a Ca-salt of an alpha-sulfonated alkyl fatty acid methyl ester, the cosurfactant (2-ethylhexyl)monoglyceride and water. As for other ternary surfactant/cosurfactant systems, the L-3-phase occurs with increasing cosurfactant/surfactant ratios after the L-alpha-phase. Some properties of the newly observed L-3-phases are the same as for other known L-3-phases. It is a low viscosity, optically isotropic fluid with a low flow birefringence. The time constants tau of the electric birefringence results scale with tau similar to O-3. Its conductivity is very much higher than that of the neighboring L-alpha-phase, but there are some marked differences from known L-3-phases. This novel L-3-phase is thermodynamically stable despite ionic structure of the surfactant. We found no two phase region between the L-alpha and the L-3-phase, and the L-3-phase is stable over a wide cosurfactant/surfactant ratio between one and two. In SANS measurements it shows a broad correlation peak that occurs at about the same position as the sharper peak in the L-alpha-phase. The structure of the L-3-phase is demonstrated by FF-TEM micrographs.