AIMS: A new self-nanoemulsifying drug delivery system (SNEDDS) was developed for erlotinib (Ert) oral delivery. MATERIALS AND METHODS: A pseudo-ternary phase diagram for olive oil, Tween 80 and polyethylene glycol (PEG) 600 mixtures, was firstly constructed. Based on the data about Ert solubility and cytotoxicity of these components, a SNEDDS composed of 10% olive oil, 20% Tween 80 and 70% (V/V) polyethylene glycol 600 was selected for Ert loading (Ert-SNEDDS). RESULTS AND CONCLUSIONS: SNEDDS formed 31.2-nm droplets upon dilution in water, and Ert loading led to increment in the oil droplets to 83.9 ± 0.6 nm. Ert-SNEDDS represented a loading capacity and an entrapment efficiency of 22.7 ± 0.7 and 40.7 ± 0.5%, respectively. Ert release from Ert-SNEDDS was monitored in both a mixture of phosphate buffer saline and 0.5% Tween 80, and artificial gastric fluid. Ert-SNEDDS was orally administrated in rats, and the Ert plasma level was monitored over time to measure pharmacokinetic parameters. Ert-SNEDDS led to enhancement in the drug bioavailability and changed the release route of Ert. Ert-SNEDDS showed enhanced cytotoxicity toward ASPC-1 and PANC-1 cells, and half-maximal inhibitory concentration values were obtained and compared with free Ert. Ert-SNEDDS may be considered as an alternative route for oral Ert delivery.