Two methods for the simultaneous estimation of atenolol and hydrochlorothiazide in combined tablet dosage form have been developed. The first method is the Q-analysis method, based on absorbance ratio at two selected wave lengths 232.0nm (Iso-absorptive point) and 270.0nm ($\lambda$max of hydrochlorothiazide). The second method is the first order derivative spectroscopy using 214.0nm (zero cross for atenolol) and 241.0nm (zero cross for hydrochlorothiazide). The linearity was obtained in both the methods in the concentration range of 1-30$\mu$g/ml and 1-40$\mu$g/ml for atenolol and hydrochlorothizide, respectively. These methods are simple, accurate and results of analysis have been validated statistically and by recovery studies.