Context. Ever since it was identified with VLT/NaCo as a bona-fide exoplanet with a mass of about 9 times that of Jupiter at an orbital separation of 8–9 AU, β Pictoris b has been one of the most studied objects nowadays. The link between the planet and the dusty disk is unambiguously confirmed, and this system provides an opportunity to study the disk/planet interactions and to constrain formation and evolutionary models of giant gas planets. Still, β Pictoris b has never been confirmed with other telescopes so far. Aims. We aimed at an independent confirmation using a different instrument. Methods. We retrieved archive images from Gemini South obtained with the instrument NICI, which is designed for high-contrast imaging. The observations combine coronagraphy and angular differential imaging and were obtained at three epochs in Nov. 2008, Dec. 2009, and Dec. 2010. Results. We report the detection with NICI of the planet β Pictoris b in Dec. 2010 images at a separation of 404 ± 10 mas and PA = 212.1 ± 0.7°. It is the first time this planet has been observed with a different telescope than the VLT.