This study examines how social trust affects firms' use of open and closed B2B e-commerce in Europe. The researchers hypothesized that higher social trust in a country would decrease use of closed e-commerce but increase open e-commerce, and that IT experience would positively impact both but its effect would be weaker on closed and stronger on open e-commerce in high trust countries. Analyzing data from over 10,000 European enterprises, the results supported these hypotheses, finding social trust and IT experience significantly impacted e-commerce adoption as predicted. The conclusion is that open e-commerce may be the future direction due to advantages, but managers should consider company characteristics and situation in choosing approach.