Both Fleming and Kallis struck 62 each and former Zimbabwe captain Flower made a quickfire 55 off 40 balls in the match which saw Indian captain Sourav Ganguly making 14 and V V S Laxman scoring almost run-a-ball 47 at the Lord's.
Sri Lankan wicketkeeper-batsman Kumara Sangakkara also used the long handle to good effect making 46 towards the end.
Put in to bat, the MCC XI were off to a sedate start with Chris Gayle and captain Fleming adding 14 runs for the first wicket before the West Indies opener was trapped leg before by Chaminda Vaas for 4.
Ganguly, a late replacement for Ramnaresh Sarwan in the MCC XI, came first down and in the company of Fleming took the team's score past the half century mark before he was castled by the Sri Lankan seamer.
Fleming and Kallis then added 62 runs for the third wicket in 10 overs before Laxman, Flower and Sangakkara upped the tempo in the later part of the innings with some lusty blows.
Vaas was highly impressive with his bowling returning with two wickets for 19 runs in seven overs. Chris Cairns and Shane Warne also claimed two wickets apiece but were quite expensive.
Virender Sehwag's off-spin was plundered for 38 runs in five overs as the International XI captain Brian Lara used 10 bowlers including himself.