A faunistic survey was conducted to find Osmia bees to be used as an effective pollinator in apple orchards. Collections were carried out from more than 50 selected sites in mountainous areas throughout Korea for 3 years (1996-98) with providing bundle of bamboo traps (6-8 mm of inner diameter) as Osmia nesting site. Five species of Osmia ：O. cornifrons (Radoszkowsky), O. pedicornis Cockerell, O. taurus Smith, O. satoi Yasumatsu et Hirashima and O. jacotti Cockerell, were collected at the rates of 39.9-51.7, 28.3-53.7, 5.5-19.1, 0.8-0.9 and 0.0-0.1%, respectively. And O. cornifrons and O. pedicornis were the dominants with over 80% of total Osmia collected through the collections. Out of those bees collected, rates of female were 29-43% for O. cornifrons. 10-12% for O. pedicornis and 22-43% for O. taurus. When the collection sites of the dominant 3 species were grouped in relation to altitudes above the sea level, about 50% or more bees were collected form the higher sites (500m or higher) while 20% or less were from the lower sites (200m or lower). When the bamboo traps were placed at the same sites continuously for 3 years, number of O. cornrfrons and O. taurus collected was slightly increased while that of O. pedicornis was drastically decreased year after year. Nesting by Osmia bees seems to have started at around early April, peaked at early May and ended by Mid June, while nest competing species of Sphecidae and Eumenidae started nesting at around early June, peaked at early July and ended by the Mid August.