In this present work Erythromycin stearate nanosuspension has been formulated. Since Erythromycin stearate is insoluble in water, it has been formulated as nanosuspension to improve bioavailability of the drug. The formulation was carried out using High Pressure Homogenization method using different variables like drug-surfactants ratio, stirring speed and rotation time, to optimize the final formulation while keeping the quantities of active ingredient constant. An optimized final formulation was prepared by using drug, poloxamer 188 and tween20 in 1:2:2 ratios with stirring speed of 25000 rpm for 25 minutes using High Pressure Homogenizer (Polytron PT 1600E) followed by lyophilisation. The optimized final formulation was subjected to in-vitro parameters such as compatibility, drug content, particle size analysis, zeta-potential, SEM, in-vitro release profile. All the in vitro evaluation parameters complied the limits. Stability studies were also conducted as per ICH guidelines and from the result it may be concluded that the optimized formulation is stable. Finally, it is concluded that the drug is compatible and stable with the excipients, hence Erythromycin stearate can be formulated as nanosuspension by this method. Key words: Erythromycin stearate, Poloxamer 188, Nanosuspension, Zeta potential, DSC, SEM.