In a one-sided game at the San Siro, Argentine striker Milito tucked in Ricky Alvarez's cross after 13 minutes before Thiago Motta drilled in a second goal from distance.
Milito headed home Maicon's centre in the 41st minute and Giampaolo Pazzini (56) and Marco Faraoni (79) finished off Parma.
Inter, who meet city rivals AC Milan next weekend, stay fifth with 29 points from 17 games while Parma remain 13th ahead of the main programme of fixtures on Sunday.
"It was important to have a good first period because Parma tend to start well with their three attackers," Inter coach Claudio Ranieri told Sky Sports.
"My players are not finished. We know we've got out of a precarious position with these five wins but we need to fly if we are going to catch those above. I'm not saying how high we can go."
Inter began confidently and took the lead when Milito, one of nine South American-born players in their starting lineup, cleverly flicked the ball in at the near post.
Strike partner Pazzini blazed an easier chance over from another teasing Alvarez cross before the in-form Uruguayan teed up Motta to double the home team's advantage with a skidding drive.
Sebastian Giovinco had a glorious chance to bring Parma back into the game but headed weakly wide after a fine Jonathan Biabiany run and cross.
Parma then went close with two rasping free-kicks before Milito nodded his second goal high into the net.
PRECISION PASS
With Inter playing on the break in the second period, Pazzini got in on the scoring act after running on to Milito's precision pass and coolly lifting the ball over goalkeeper Antonio Mirante.
An assistant referee's flag saved the blushes of Inter skipper Javier Zanetti after he belted the ball into his own net from the edge of the box before substitute Faraoni delivered a superb half-volley that crashed in off the underside of the bar.
"We allowed Inter to do too many easy things and we didn't take our chances," said Parma coach Franco Colomba after his side extended their run to six games without a win.
"We know where we need to improve. We have to find the right balance between attack and defence."
In Tuscany, two goals each from Emanuele Calaio and Mattia Destro led struggling Siena past Lazio as Serie A returned after a two-and-a-half week break.
Siena, who had not scored in their five previous league matches, struck three times in the opening half through Destro's early strike and two Calaio penalties.
With Lazio reduced to 10 men after goalkeeper Albano Bizzarri was dismissed for complaining about the second spot-kick, Destro added his second goal late on.
