The current study is focused on referential ambiguity - a situation when a pronoun may be interpreted in favor of several referents. In the eye-tracking study, we aimed to investigate how referentially ambiguous and unambiguous sentences are processed when the readers' expectations are manipulated by context. Two stimuli groups with temporal ambiguity were used: a region with a pronoun was followed by a clause containing disambiguating information. A control unambiguous condition was created for each experimental item. In the first group, there was no specific bias towards any of referents, while in the second group the readers' expectations were biased towards the first-mentioned referent. The results showed that expectations are formed even before the pronoun appears. In the second group in the unambiguous condition it results in a slowdown at the pronoun region when it refers to the unexpected referent. The ambiguous condition allows interpreting the pronoun according to the readers' expectations, so the slowdown occurs only in the disambiguating area when the pronoun is disambiguated towards a less anticipated referent. In both cases the slowdown reflects reprocessing of the text and correcting the discourse representation. As for the stimuli with no predetermined expectation, there was no difference in the first-pass reading time of the region with a pronoun; however, the significant slowdown in the processing of disambiguating area is reported in the ambiguous condition compared to the unambiguous one, regardless of which referent the pronoun refers to. This may be caused by retrieval difficulty, by the necessity to reprocess the previous text or to establish referential relations.