An automatic folding knife having a sear provided on a pivoting blade, and an engagement member, configured for upward movement, for selectively engaging the sear. The engagement member extends generally to the exterior of each side portion of the handle. A spring-biased cable biases the blade towards the extended position, and the engagement member is configured for engaging the sear upon the blade being in the retracted position. The blade is configured to automatically pivot from the retracted position to the extended position upon the engagement member being lifted upwardly, and the engagement member also automatically locks the blade in the extended position. The knife can readily be converted to an assisted opening knife having in significant part the components of the automatic knife.