Purpose: To evaluate clinical results of the 5th proximal metatarsal intraarticular fracture (Zone I) with displacement treated operatively and to evaluate predisposing factors of the 5th proximal metatarsal fracture (Zone I). Materials and Methods: 11 patients treated for the 5th proximal metatarsal fracture (Zone I) operatively and 10 patients treated conservatively between Jan 2003 and Dec 2005, were followed for more than one year. Functions were graded by AOFAS foot scoring system and union time and postoperative complications were also evaluated. Calcaneal pitch angle was also evaluated. Results: Clinically there were no much difference in results. Clinical points were 94.5 in the operative group and 92.3 in the conservative group. At the last follow-up, the radiographic results showed union in all cases. During the follow-up period, there were no significant complications. But in the conservative group, displaced fracture with calcaneal pitch angle over 30 degree tends to show delayed union and time to loss of pain tends to be prolonged. Conclusion: Calcaneal pitch angle is thought to predisposing factor for 5th metatarsal base fracture. Operative treatment is viable option for the 5th proximal metatarsal intraarticular fracture with displacement and with calcaneal pitch angle over 30 degree. In cases of cavovarus foot deformity, we think operative treatment should be considered with deliberation and long term follow-up study for peroneal tendinopathy should be needed.