The investigation of the comprehension of L1 relative clauses across different languages has shown that subject relatives (SRs) are acquired earlier and responded to more accurately than object relatives (ORs). Most of this work has been based on SVO nominative-absolutive languages. In this article we present the results obtained in a binary picture-sentence matching task from L1 Basque, a highly inflected, ergative-absolutive, SOV language with prenominal relatives. The results obtained reveal that in Basque, ORs are responded to more accurately than SRs, which indicates that children do not comprehend SRs with more accuracy universally. The results are discussed in the light of different hypotheses put forward in the literature in order to account for the previously observed SR preference. (Contains 5 tables and 17 footnotes.)