Garzelli also won Saturday's mountain stage of the race

France's Laurent Mangel finished one minute and one second behind while Ricardo Serrano of Spain was third.

Italy's Danilo di Luca retained the overall lead after finishing in the main bunch, eight minutes and 10 seconds behind Garzelli.

The Italian was in an eight-man group that broke away on a downhill stretch to finish in five hours, 34 minutes.

It was his second stage win in the 2007 race, which visited Austria for a single day.

Wednesday's 17th stage goes from Lienz to the summit of Monte Zoncolan in Italy with the 10km climb to the finish line considered the steepest ever used in a professional cycling race.

Meanwhile Spain's Aketza Pena Iza, who was 51st overall after the stage, quit the race after being suspended by his team following a positive A test for the banned substance nandrolone in the Tour of Trentin in April.

The Euskaltel-Euskadi team said they had told him to leave the Giro as a precautionary measure.

Stage results
1. Stefano Garzelli (Ita/ Acqua & Sapone ) 5:34:07"
2. Laurent Mangel (Fra/AG2R ) +1:01"
3. Ricardo Serrano (Sp/Tinkoff ) same time
4. Jose Luis Rubiera (Sp/Discovery Channel ) same time
5. Pietro Caucchioli (Ita/Credit Agricole ) same time
6. Pablo Lastras (Sp/Caisse d'Epargne ) same time
7. Salvatore Commesso (Ita/Tinkoff ) +2:29"
8. Giovanni Visconti (Ita/Quick-Step ) same time
9. Assan Bazayev (Kaz/Astana ) same time
10. Lorenzo Bernucci (Ita/T-Mobile ) same time

Overall standings:
1. Danilo Di Luca (Italy / Liquigas ) 73:43:12"
2. Eddy Mazzoleni (Italy / Astana ) +1:51"
3. Andy Schleck (Luxembourg / Team CSC ) +2:56"
4. Gilberto Simoni (Italy / Saunier Duval ) +3:19"
5. Damiano Cunego (Italy / Lampre ) +3:23"
6. Riccardo Ricco (Italy / Saunier Duval ) +3:39"
7. David Arroyo (Spain / Caisse d'Epargne ) +6:05"
8. Emanuele Sella (Italy / Panaria ) +7:02"