A 43-year-old female patient developed bilateral ophtalmoplegia, bulbar paresis and weakness of the respiratory and extremity muscles. Additionally she had decreased sensation on the left half of the body. Repetitive nerve stimulation (RNS) test confirmed the diagnosis of botulism and edrophonium injection caused a reduction in the decremental response. When in doubt, RNS testing can provide the definitive results in the diagnosis of botulism.