
Hamilton registered a time of 1 minute 28.469 minutes for the 5.338-kilometre Istanbul Park circuit, 0.293 seconds quicker than Kimi Raikkonen in a Ferrari.
The Toyotas of Ralf Schumacher and Jarno Trulli registered the third and fourth fastest times, respectively, in the session.
Defending world champion Fernando Alonso in a McLaren- Mercedes was fifth fastest, followed by Nico Rosberg in a Williams.
Raikkonen clocked the fastest time of day in the first session with a lap time of 1:27.988 minutes. Team-mate Felipe Massa was second fastest in 1:28.391.
Alonso was third in the earlier session, followed by Hamilton.
Renault's Heikki Kovalainen was fifth fastest with Rosberg sixth.
Hamilton heads the drivers' standings on 80 points with six races remaining, seven clear of Alonso in second. Raikkonen lies third on 60 points, one ahead of Massa.
DPA