The equilibrium partitioning of a 1,3-dioxolane (pH-degradable) alkyl ethoxylate surfactant in 2- and 3-phase microemulsion systems formed from equal volumes of water and isooctane was determined as a function of temperature (20-50oC) and surfactant concentration (5-10 wt. %), in single and binary surfactant systems, the latter with Aerosol-OT and octyl-beta-D-glucoside. The head group of the surfactant molecules consist of poly(ethylene glycol) monomethyl ether (or MPEG) with degree of polymerization distributed around the average value of 7.2 as a Poisson function. Semilog plots of partition coefficient (surfactant concentration ratio of isooctane to water-rich phases) versus MPEG degree of polymerization correlate well to straight-line models, consistent with theory and previously published results for alkyl ethoxylate surfactants. The slope and the y-intercepts of the linear models are strong functions of temperature. The addition of a second surfactant had only a minor effect on the equilibrium partitioning of the 1,3-dioxolane surfactant.