This paper studies pull-in behavior of a bio-mass sensor with a cantilevered CNT actuated electrostatically considering rippling deformation. Although this phenomenon can change the behavior of CNT remarkably, its effect on the performance of a CNT-based mass sensor is not investigated yet. This investigation is based on modified Euler-Bernoulli beam theory and rippling effect is entered the equations related to cantilevered CNT-bases sensor. Impact of other properties like different masses, mechanical damping and intermolecular force is studied in this paper too. According to the results obtained from this study rippling deformation decrease the pull-in voltage and tip deflection of CNT while it enhances the pull-in time. Results related to the impact of other mentioned properties are presented too. In order to verify the soundness of this study, the obtained results are compared with other pull-in sensor equations in literature and “molecular dynamics”, and an excellent agreement is seen in both.