Abstract. We present results of a multi-wavelength study of nearby (z = 0.03) TeV Blazar Mrk421. Mrk421 is in the high state of activity since November 2009 and has shown flaring behaviour in X-ray and gamma ray bands in February 2010. One of the brightest flaring episodes of this source was observed by various experiments on 17th February 2010. We have observed this source in bright state using High Altitude GAmma Ray (HAGAR) telescope array at energies above 200 GeV during 13 - 20 February 2010. HAGAR has detected Mrk421 at the flux level of about 6 Crab units on 17th February and this is consistent with detections reported by other very high energy experiments. We present the spectral energy distribution of the source during this flaring episode. Also using soft X-ray data from ASM on board RXTE, hard X-ray data from BAT on board Swift and gamma ray data from LAT on board Fermi in association with HAGAR data, we have investigated the correlated variability.