The Foxes looked to be on course for a deserved victory when Iain Hume finished confidently in the 85th minute, but Moroccan striker El Hamdaoui cancelled that out with an equally good strike five minutes later.
The draw was probably just about right although Leicester will look back on missed chances and an offside decision which denied Elvis Hammond a goal in the 55th minute.
The prospect of either side finding the net looked remote after a desperately poor first half, in which the ball was given away needlessly.
Although Derby forced five corners in quick succession, keeper Paul Henderson was never seriously threatened and it was Derby's 42-year-old goalkeeper Kevin Poole who made the most telling save when he tipped over a 25-yard shot from Danny Tiatto.
The quality and entertainment improved after the break with the introduction of on-loan Arsenal winger Ryan Smith sparking the visitors into life.
Smith was a constant threat with his pace and willingness to run at defenders and he almost put Hume in in the 63rd minute, only for Poole to just beat the Canadian international to the ball.
Derby also made changes although the home fans booed loudly when Paul Peschisolido was taken off and replaced by El Hamdaoui.
They obviously thought it should have been Stern John who made way and the on-loan Coventry striker did not improve their mood when he fired a shot wide and then saw Henderson tip a low drive away for a corner.
John was substituted by Dean Holdsworth, but the 36-year-old striker wasted an excellent chance when he headed wide following a corner.
Poole was having a better afternoon, saving well with his legs to deny Smith in the 76th minute, but City finally made a chance count with five minutes remaining.
Substitute Patrick Gerrbrand knocked a ball through the middle from out on the right and Hume got behind Jeff Kenna to beat Poole as he came off his line.
That looked to have settled the game but with time running out, Adam Bolder put El Hamdaoui in on the Leicester left and the on-loan Spurs striker flashed a right-foot shot across Henderson and into the bottom right-hand corner.