The influence has been studied of the addition of lanthanum to coprecipitated Ni-Al catalysts used in the catalytic steam gasification of biomass. The experimental work was carried out at a relatively low temperature, 700 degreesC, and at atmospheric pressure. Three Ni-Al-La catalysts were prepared, the Ni content being the same in all cases but with varying amounts of La and Al. The evolution of gas yields over time was analysed and the results obtained with the modified catalysts compared with those corresponding to the Ni-Al catalyst. The addition of lanthanum to the Ni-Al catalyst resulted in an increase in CO, CO2, CH4, C-2 and total gas yields, while the H-2 yield remained almost unchanged. This demonstrates that when the Ni-Al catalyst includes lanthanum in its formulation, a higher transformation of the carbon contained in the biomass to valuable gases takes place and, consequently, less coke is formed over the catalyst. These effects were also analysed in relation with another reaction, CO2 reforming of CH4, where similar trends were noted. (C) 2003 Elsevier B.V. All rights reserved.