Recent studies showed instability of poly (amidoamine) (PAMAM) dendrimers during interaction with surfactant (SDS). Modification of PAMAM dendrimers by grafting mono methoxy poly (ethylene glycol) (MPEG) chains at PAMAM surfaces was carried out to achieve colloidal stability in the presence of an anionic surfactant. The Michael addition reaction was employed to synthesize PEGylated PAMAM by activating MPEG with 4-nitrophenylchloroformate. 1HNMR spectrum confirmed that 32 MPEG chains were successfully grafted onto a 6.8 nm PAMAM particle to provide sterle stabilization against precipitation in the presence of an anionic surfactant. No precipitation was observed when the SDS concentration was between 0.001 roM to 100 roM. In addition, isothermal titration calorimetric (ITC) and zeta potential measurements provided information needed to elucidate the binding mechanism of SDS with PEGylated PAMAM. This study provides useful fundamental insights on the interaction of PEGylated PAMAM with amphiphilic molecules, such as drugs that enhances our understanding on the use of PEGylated PAMAM in drug delivery applications. The varieties of surfactants make this system very promising in addressing various theoretical and practical applications, particularly in pharmaceutics.