This study aims to describe a local network for physical activity promotion and identify factors associated to collaboration or partnership ties between its actors. The study was carried out in a district of São Paulo, Brazil. Thirty-two actors responsible for policies, programs, and initiatives to promote physical activity within the district were interviewed from June to December 2012. Interviews included information about the actors' attributes and their relationships with the other actors. Network analysis techniques were used to describe and analyze the structure of the network. Thirty-two actors maintained 179 relationships among themselves (density = 0.18), of which 46% were reciprocal. Four in 10 relationships did not extend beyond information exchange. Forty-six relationships were classified as collaborations or partnerships (density = 0.09), of which 40% were concentrated on one actor of the public sector. To perceive institutional structure and bureaucracy as limiting factors to networking has been positively associated with new collaboration or partnership ties (OR = 2.37; 95%CI: 1.2-5.50). Understanding the structure of the network may empower the actors and foster self-management, facilitating the identification and decision, in a collaborative way, in which new relationships may have greater impact in the physical activity promotion within the district.