The Bulgarian striker moved to the Stade Louis II for the remainder of the campaign from Premier League strugglers Fulham in January.
And having scored four times in eight appearances since his temporary switch, Ranieri feels 33-year-old Berbatov is enjoying life in Ligue 1.
"Slowly, he gets better. This is a good player and he is very important to us," the Italian told L'Equipe.
"I think he wants to stay. We will talk together later."
Berbatov was on target in Wednesday's 6-0 rout of Lens as Monaco moved into the last four of the Coupe de France.
Ranieri's side will face Guingamp in the semi-finals on April 15.
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