Improved analytical capability for detection of organophosphate chemical agents (i.e. nerve gases) remains a high priority need in our continuing defense against future terrorist attacks. A stochastic sensing method for the detection of organophosphate compounds has been developed by using single channel recording with lipid bilayer technique. A molecularly tailored alpha-hemolysin protein pore interacts with organophosphates. By monitoring the ionic current passing through the single protein nano-pore at a fixed transmembrane potential, individual binding events are detected as transient blockades in the recorded current with sub-millisecond time resolution. Our experiments also show that the target organophosphate and false positives could be successfully differentiated, and even simultaneously detected. Common interferents will not interfere with the organophosphate detection in a wide dynamic range. Therefore, this approach has a potential to be developed as a rapid and sensitive method to detect organophosphates in an aqueous environment at the single-molecule level.