Turbulent fluctuations of wind and temperature were measured using a three-component sonic anemometer at 8 m on a 30 m micro-meteorological tower erected at the Indian Institute of Technology (IIT) Kharagpur (22.3" N, 87.2" E), India, as part of the Monsoon Trough Boundary Layer Experiment (MONTBLEX). Diurnal and nocturnal variations of fluxes of sensible heat and momentum were estimated by the eddy correlation technique from 42 observations, each of 10 min duration during 6-8 July in the monsoon season of 1989. The estimated heat flux shows a diurnal trend while the momentum flux shows variability but no particular trend. The nocturnal heat flux changes sign intermittently. Fluctuations of vertical wind velocity u,, and temperature oH when normalised with the respective scaling parameters IL* and 0, are found to scale with Z/L in accordance with the Monin-Obukhov similarity hypothesis: & x (Z/L)"', +e x (ZIL)m"3 during unstable conditions and 4,, x (Z/L), & = (Z/L)-'during stable conditions. Correlation coefficients for heat and momentum flux Y,,+ and Y~,,~ show stability dependence. For unstable conditions, y,, B increases with increasing /Z/L 1 whereas Y!,,~ decreases. During stable conditions, Y,~@ decreases with increasing Z/L while Y,,,~ decreases very slowly from a value -0.36 to -0.37.