This invention provides an image capturing lens system in order from an object side to an image side comprising four non-cemented lens elements with refractive power: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power having a concave image-side surface; a plastic third lens element having a concave object-side surface and a convex image-side surface, both the object-side and image-side surfaces thereof being aspheric; and a plastic fourth lens element with negative refractive power having a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein the image capturing lens system comprises a stop positioned between the first lens element and the second lens element.