The home side started well, with influential French midfielder Christophe Cocard being the difference between the sides in the opening quarter. Cocard came close in the second minute of the game with a low drive, but he failed to trouble ex-Scotland international Jim Leighton.
Cocard came close again when he hit a shot on the volley from outside the box, but Leighton stood up to the shot once again. Moments later, Andy Smith set up Cocard, and the Frenchman tried a speculative effort, which was off target.
The breakthrough came in the 23rd minute. Young Scot Gary Holt broke free and crossed for ex-Don PAUL WRIGHT to make it 1-0 to Kilmarnock.
Kilmarnock continued to have the best of the possesion with Ian Durrant and Gary Holt, instrumental in the middle of the park. Durrant gave Holt the opportunity to extend their lead, but Leighton was quick to get down at the feet of Holt, just as it looked like being 2-0.
Into the second half, and things didn't get much better for the Dons. Kilmarnock substitute Sammasi Abou came close to heading past Leighton, after good work out wide from Ian Durrant.
Aberdeen had chances, notably through Arild Stavrum and Eion Jess, but they couldn't break down the Rugby Park side's defence. The defeat leaves the Dons 7 points adrift at the bottom, with only 3 games at Pittodrie left this season.