The aim of this study was to develop a structure-property model for membrane partitioningof oligopeptides using statistical design methods and multivariate data analysis. A set of 20tetrapeptides with optional N-methylations at residues 2 and 4 was designed by a D-optimaldesign procedure. After synthesis and purification, the membrane partitioning abilities of thepeptides were tested in two chromatographic systems with phospholipids as the stationaryphase: immobilized artificial membrane chromatography (IAM) and immobilized liposomechromatography (ILC). The relationship between these measures and three different sets ofcalculated descriptors was analyzed by partial least-squares projection to latent structures(PLS). The descriptors used were the molecular surface area, Molsurf parameters, and Volsurfparameters. All three models were of good statistical quality and supported that a largehydrogen-bonding potential and the presence of a negative charge impair membrane partitioning,whereas hydrophobic parameters promote partitioning. The findings are in accordancewith what has been found for absorption of known drugs and have implications for the designof peptide-like drugs with good oral bioavailability.