We report the effect of BaO addition on thermal, crystallization, electrical and mechanical behavior of the magnesium lanthanum alumino borosilicate glass-ceramics. The glass forming region has been found to be quite narrow with respect to BaO content. Casting and annealing of completely transparent and amorphous glasses within this system has been possible only at an optimum BaO content of 25 mol% without any La(2)O(3) and Al(2)O(3). On further optimization of the developed glasses in terms of different borosilicate ratios, one of the developed compositions having MgO and BaO content of 22 and 25 mol% respectively, with a glass former ratio of 3 (SiO(2):B(2)O(3)) has been found to be quite promising in terms of its mechanical property, excellent joining, minimum chemical interaction and lowest leak-rate with the metallic interconnect such as Crofer22APU, and thus fulfills the major requirements for SOFC sealing application. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.