This article presents the results of a nonce-probe experiment 
 conducted with 13 native speakers of Russian and examines the 
 implications of these results for the linguistic analysis of 
 Russian stress. Experimental items were novel words that ended 
 in a sequence of segments either homophonous with a Russian 
 case ending or not. Carrier sentences were manipulated to either 
 morphosyntactically support a case-marked form or not. Results 
 show a strong morphological effect: speakers stressed the last 
 syllable of the stem, i.e., the ultima in words without 
 inflections, and the antepenult or penult in words with 
 inflections (depending on length of the inflection). This 
 finding is relevant for linguistic analysis of Russian because 
 it uncovers a default location for stress that is not abundantly 
 apparent in the synchronic phonology. A new formal analysis is 
 presented in Optimality Theory that makes crucial use of an 
 interface constraint that governs the alignment of prosodic 
 structure (stress) and morphology (the right edge of the stem), 
 and the OT concepts of faithfulness and anti-faithfulness.