The Indomitable Lions have now qualified for an African-record six World Cup finals appearances.
Cameroon started the final day of Group A action just a point ahead of Gabon but their progress to South Africa was never in any doubt after they scored on 17 minutes against a depleted Morocco.
A shot from Spanish-based Achille Webo caught the home defence unawares.
Samuel Eto'o grabbed the second goal seven minutes into the second half with a shot from the outside of his boot after a header into the penalty box from Jean Makoun. It was his ninth goal in 11 starts in the 2010 qualifiers.
Cameroon had been bottom of the group standings in mid-year, leading to the firing of German coach Otto Pfister.
His replacement, Frenchman Paul LeGuen, engineered the recovery, appointing Eto'o as captain, and won four successive qualifiers to ensure top place in the group.
Cameroon finished on 13 points, four clear after Gabon lost away to Togo who won thanks to a 71st minute goal from Emmanuel Adebayor.
Before the match, Adebayor had promised to double his team -ates' match bonus if they won.
Togo finished third in the group to secure an African Nations Cup final berth in Angola in January.
