Which Mario Party game is the last one developed by Hudson Soft?

Mario Party DS is the last Mario Party game developed by Hudson Soft.

Released for Nintendo DS in 2007, Mario Party DS continued the series’ established formula: players moved around a themed board, collected stars and competed in minigames. It also used the handheld’s dual screens, touchscreen and microphone for several challenges. The game was developed by Hudson Soft and published by Nintendo.

Its place in the series’ development history is what makes the answer distinctive. Hudson Soft created the Mario Party games from the original Nintendo 64 release through Mario Party DS. After that, Hudson’s role ended, and later mainline entries were developed by Nintendo Cube, now known as NDcube. Mario Party 9, released for Wii in 2012, was the first main series installment developed by that newer team.

A common mix-up is Mario Party 8, because it was the final Hudson-developed console entry before the Nintendo DS title. Mario Party Advance was also developed during Hudson’s era, but it came earlier, in 2005. Mario Party DS therefore is the final Hudson Soft game in the series overall, not merely the last handheld installment.