Name : Peter Tinyakov E-mail : Peter.Tinyakov@cern.ch TITLE : Clustering of UHECR and their sources. ABSTRACT : We calculate angular autocorrelation function of UHECR observed by AGASA and Yakutsk experiments and find significant correlations at small angles corresponding to the expermantal resolution. We then look for extragalactic sources which are responsible for these autocorrelations. We find correlations with BL Lacertae at angles 2.5^o with the probability of a chance coincidence 10^{-5}. We identify some of BL Lacertae as sources of UHECR.