A NotI end clone library has been constructed from a human-hamster hybrid cell line containing only human chromosome 11. Fifty-one NotI clones were chosen to characterize the library. The majority of NotI clones hybridize to small 15- to 200-kb fragments and have proven to be valuable for chromosome 11 physical mapping by detecting fragments not previously recognized by random probes. These NotI end clones have been used to isolate corresponding NotI linking cosmids which were then used to identify adjacent NotI fragments on pulsed-field gels. The clones were mapped using fluorescence in situ hybridization and a somatic cell hybrid panel. Although these clones were localized over the entirety of chromosome 11, a nonrandom distribution was observed. Northern blot analysis indicated that 57% (17/30) of the NotI clones examined detected poly(A)+ transcripts in HeLa cell RNA.