  Markarian 421 (Mrk 421) is one of the brightest, fastest and closest BL Lac
object known. Its very high energy (VHE) spectrum has been successfully modeled
with both leptonic and hadronic models and not conclusive results have been
achieved yet about the origin of its VHE emission. Here we investigate the
possibility that a fraction of the VHE flares of Mrk 421 are due to hadronic
processes and calculate the expected neutrino flux associated. We introduce the
obtained neutrino flux in a Monte Carlo simulation to see the expectation for a
Km$^{3}$ Cherenkov neutrino telescope.
