Sumatriptan, an antimigraine drug has poor bioavailability (15%) due to hepatic first pass metabolism. The aim of the present investigation was to develop sumatriptan loaded solid lipid nanoparticles (SLN) for improving oral bioavailability. Sumatriptan loaded solid lipid nanoparticles was developed by emulsification – ultrasonication method. A 32 factorial design was employed: two factors such as drug: lipid ratio and lipid: surfactant ratio were the independent variables used. Parameters investigated included particle size, polydispersity index (PDI), zeta potential, % entrapment efficiency (%EE), in-vitro drug release of the SLNs. Optimized SLNs had particle size of 150.2 nm, zeta potential of - 31.6 mV, %EE of 86.28 % and cumulative percent drug release of 69.57 % in 10 h. The pharmacokinetic study of optimized SLNs conducted in male Albino Wistar rats showed 2.79 fold increase in relative bioavailability than that of sumatriptan solution, when administered orally. The enhanced relative bioavailability by the SLNs formulation might be attributed to avoidance of first- pass metabolism by lymphatic transport. TEM study confirmed particles had asymmetrical and circular shape.