The effect of dissolved gas on the hydrophobic attraction between double-chained surfactant monolayersphysisorbed on mica has been studied using a surface forces apparatus (SFA). Distance vs time data wereobtained over the full distance regime from D ≈ 1000 Å down to contact using the dynamic SFA method.Removal of dissolved gas was seen to reduce the range of the attraction while the short-range attraction(under ∼250 Å) remained unchanged. The implications for the possibility of two distinct force regimes inthe interactions between hydrophobic surfaces are discussed.