Background: The important role of phonological processing for reading has been demonstrated by many studies. The purpose of this research was to investigate the role of phonological processing for reading in Russian. Specifically, we tested whether the overall complexity of a phonological task predicts reading fluency and reading comprehension. Method: We used seven phonological tests ranked according to the number of linguistic processes involved in each task. We examined the relative difficulty of the tests and the relationship between phonological processing and reading skills (reading fluency and comprehension of simpler and more difficult texts) in 90 typically developing 7 to 11 years-of-age Russian-speaking children. Results: Phonological tests that involved more linguistic processes had lower response accuracies. At the individual level, a greater estimated cost of adding a linguistic process to a phonological test was associated with a reliable decrease in reading fluency but not reading comprehension. Conclusions: Our findings confirmed the substantial role of phonological processing in reading acquisition while stressing a higher predictive value of more complex phonological tests for reading fluency. The relationship between phonological processing and reading comprehension, in Russian, needs further investigations.