Four Ba-promoted Co-Ce catalysts for NH3 synthesis were prepd. by copptn. with K2CO3 from aq. solns. of Co(NO3)(2) and Ce(NO3)(3) and calcination at 500 degrees C or 800 degrees C for 24 h and following impregnation with Ba(NO2)(2). The catalysts were tested by thermogravimetric anal., physisorption of N-2 and temp.-programmed desorption of H-2. Their catalytic activity was tested under industrial conditions of the NH3 synthesis (400 degrees C, 6,3 MPa). The increase of calcination temp. from 500 degrees C up to 800 degrees C had an unfavourable effect on textural parameters and the activity of the catalysts. The activity of the catalysts was higher than that of the corn. Fe catalyst.