Police said the bomb went off in the parking lot of the Makka Al Mukarram hotel, a hotel with tight security and which is popular among government officials and businessmen.
Security sources said the driver of the car fled the area before the bomb went off. They said one person was killed and another injured.
The hotel has been attacked by Somalia's Al-Qaeda-affiliated Shebab militants in the past, and the bombing comes several weeks after the Islamists carried out a suicide raid against another hotel in the city, killing at least 25 people.
The group regularly targets hotels, the international airport, the presidential palace known as Villa Somalia and other high-profile targets.