Both countries missed out on the last finals earlier this year but are hoping to return to the continent's top soccer tournament despite missing key elements of their squads.
Cameroon play away in the Cape Verde Islands without captain Samuel Eto'o, who is boycotting the team at the end of an eight month suspension after accusing the national federation of poor management.
Nigeria, who are also away against Liberia, dropped both Peter Odemwingie and John Obi Mikel from their squad in an unexplained decision by new coach Stephen Keshi.
Senegal are also in search of a measure of redemption after a disastrous Nations Cup tournament in Equatorial Guinea and have recalled Demba Ba and Moussa Sow for their key tie against the Ivory Coast away.
The meeting in Abidjan pits two of last year's form sides together and has been eagerly anticipated since July's draw.
"It's a most important game that will we need to be on form for because we have the away leg to come in Dakar," Ivorian captain Didier Drogba told reporters in midweek.
Champions Zambia are also in a tricky tie, hosting the first leg against Uganda in Ndola.
"It's been the case for a long time that it is always difficult to qualify for the Nations Cup," said Zambia coach Herve Renard, who still has the bulk of his Cup winning squad.
Libya are again forced to shift their home match to a neutral venue because of the security situation in their country and have chosen Casablanca in Morocco to host Algeria.
The return legs will be played on the weekend of Oct. 12-14 and the 15 winners compete in next year's finals in South Africa along with the host nation from Jan. 19-Feb. 10.
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