The first explosion hit a market and the second a densely populated neighborhood, both in the capital of Cameroon's Far North region, Maroua, a military source said.
No one claimed responsibility, but Boko Haram has stepped up attacks on the countries bordering its northeast Nigerian stronghold - Chad, Niger as well as Cameroon.
All three have contributed troops to a regional offensive against the terrorist group who has allied themselves to the Islamic State in Iraq and the Levant (ISIL) terrorist group and poses one of the biggest security threats in the combustible region.
"People were running in all directions," said Celestin, a teacher, who said he had just arrived at the city's central market when the first bomb went off.
Reuters' television images showed the market littered with debris as military and health officials removed corpses from the scene wrapped in sheets.
A statement from the office of President Paul Biya said 13 people were killed in the attack. Cameroon state television channel CRTV quoted the region's governor as saying that 17 people died.
The blasts came 10 days after two suicide attacks killed 13 people in Fotokol, about 300 km (200 miles) north of Maroua.