All salmonid broodfish has been screened for Renibacterium salmoninarum with a cultural method since 1987. In 1991 a new and more sensitive method, ELISA, revealed high frequency of R.s. in kidneys of brown trout broodfish from Veidivoetn and Kvislarvoetn and in arctic charr from 3 rivers. The cultural method was persistently negative. In the summer of 1992 a screening for R.s. was performed on salmonids i.e. brown trout and arctic charr from Veidhivoetn. This study confirmed that the high frequency of R.s. was valid for the population of salmonid in these lakes. The following screening for R.s. is performed in cooperation with the following institutes: Agricultural college, Holum; Institute of Biology, University of Iceland; Institute of Fresh Water Fisheries and Natural Science Center of Kopavogur which are carving out a detailed survey of the biology of 100 different Icelandic lakes. The main aim of the study is to find out whether R.s. is commonly found in salmonids from lakes. If so, what is the common frequency of R.s. in fish populations and is R.s. more connected to one kind of a lake than another one? In the summer of 1993 this screening for R.s. was done on salmonids i.e. brown trout and arctic charr from 10 out of these 100 lakes. R.s. was detected in salmonids from 5 of 10 lakes and the frequency ranged from 3%-13% between the lakes. We hope to be able to continue the survey next year. This work is granted by The Icelandic Council of Science.