With the Ivory Coast and Mali drawing by the same scoreline earlier on Saturday, the opportunity to take the outright lead in the pool was on offer.
Volker Finke's Cameroon - who drew 1-1 with Mali in their opening match - struck first when Benjamin Moukandjo scored direct from a corner.
However, Guinea restored parity shortly before half-time courtesy of Ibrahima Traore's accurate drive.
Cameroon created the better openings in the second half with Vincent Aboubakar wasting the best chance when he put a free header wide inside the penalty area.
Each of Group D's four matches have now ended 1-1 despite stoppage-time drama that saw Stephane Mbia head wide when in a great position for Cameroon and Ibrahima Conte have strong penalty claims dismissed for Guinea.
Cameroon will now meet the Ivory Coast, while Guinea face off with Mali in order to determine who will reach the quarter-finals in the final round of pool matches.
