Pablo Armero put the hosts in front in the 20th minute and their top scorer Antonio Di Natale got his name on the scoresheet once again to make it 2-0 in the 53rd minute.
Francesco Lodi grabbed a consolation for Catania in the fifth minute of stoppage time from the penalty spot.
Di Natale has now scored in 13 of Udinese's 14 home matches, boosting his chances of earning a call-up to the Italy squad for Euro 2012 as he remains on course to clinch the Serie A top-goalscorer award for the third season running.
Overall, he has found the back of the net 14 times this season, accounting for over half of the Bianconeri's goals.
He was in position to score the opening goal in the 20th minute, and it looked like Armero had tried to find him at the far post when the Udinese full-back actually found the back of the net.
He was put through on goal by Mauricio Isla and he beat Andrea Campagnolo with what seemed like a pass for his team-mate, although the ball rolled into the bottom corner without any need for Di Natale's intervention.
Catania responded well and enjoyed most of the possession in the first half with Alejandro Gomez missing a chance to beat Samir Handanovic in a one-on-one situation in the 38th minute.
The Slovenia goalkeeper made a good save low to his left to deny him.
Di Natale got his now customary goal in the 53rd minute when he rifled in an unstoppable left-footed volley from eight yards after Armero lifted the ball back to him from the goal line.
Udinese wasted the chance to make it three in the 58th minute when they failed to make anything of a three-against-one situation on the counter attack.
Lodi tested Handanovic with a direct free-kick in the 68th minute as Udinese retreated, defending their advantage.
However, they failed to keep a clean sheet as Gelson Fernandes gave away a disputable penalty deep into stoppage time and Lodi scored from the spot.