Root has registered six Test hundreds this year
England captain Joe Root replaced New Zealand counterpart Kane Williamson as the top-ranked Test batsman Wednesday, riding his red-hot form in the ongoing five-Test series against India.
Root began the series fifth in the batting charts but smashed three centuries in as many Tests against Virat Kohli's men to reclaim the top position after a six-year gap.
The 30-year-old is the leading scorer in the series with 507 runs from five innings and has registered six Test hundreds this year.
Australia run-machine Steve Smith is third in the latest official rankings, ahead of compatriot Marnus Labuschagne.
India opener Rohit Sharma completes the top five, overtaking his captain Kohli, who has had a subdued series in England.
Veteran England seamer James Anderson entered the top five in the Test bowling rankings after his consistent performance against India.
The series is level at 1-1 going into the fourth Test scheduled at the Oval from Thursday.