Modeling and simulation of packed bed systems operating non-isothermally require sufficiently accurate knowledge of thermal transport properties. Effective thermal conductivity (k) of packed bed of molecular sieves is rarely reported. In this paper, dependence of k on temperature for a packed bed of 13X molecular sieves has been determined. An electrical heater embedded coaxially in the bed was used to heat it, and the radial temperature profiles thus obtained under transient-conditions were utilized for estimation. The estimated relationship is k = 8.17635 x 10(-5) + 10.915427 x 10(-7)(T - T-o). Statistical analysis of the estimated parameters has also been carried out. The deviations between experimental and predicted temperatures are less than 5%.