The effects of pressure on the behavior of revese micelles is not well characterized, although surfactants are commonly used in systems at pressures greater than ambient. In this paper we describe the behavior of AOT (Aerosol OT) reverse micelles in chloroform and in benzene at ambient and at elevated pressure. Observations of the critical micelle concentration (cmc) were made by monitoring the chemical shift of water protons as a function of changing AOT concentrations in the solvent-surfactant systems using H-1 NMR spectroscopy. The chemical shift of protons on the AOT molecule were also found to yield reliable information about the onset of the cmc. The cmc of benzene was not affected by an increase in system pressure, but the cmc of chloroform changed by over an order of magnitude. Observations of reverse micelle behavior in mixtures of carbon dioxide and benzene are also presented. A high pressure sample apparatus, much simpler to construct than those previously described in the literature and highly reliable at modest pressures (100-250 bar), is described.