Storing luggage in Venice before taking the night train to Vienna

I don't know the exact location, but there are left luggage facilities at the Venezia Santa Lucia train station.

Thanks, it sounds great. By any chance you would know the cost and if the service is open 24 hours. Thanks again.

I can't remember where I found this information probably on www.tripadvisor.com but we are also needing to leave our luggage for our one day outing in Venice. This information is for the St Lucia train station: left Luggage office on floor 1 near platform 1. Open until midnight. Cost is 5,70E for up to 12 hours. I know that there was a price quoted for longer times but I only needed up to 12 hrs, so that is what I wrote. Maybe this will be of some help to you.

Louis, here is what I found.
A left-luggage office (baggage room) is available beside of track 1 (this is in the Venice Santa Lucia station), opening hours: 6am-11,50pm. The price per piece is 4.00 euros for the first five hours. Rate for seven following hours: 0.60 € per hour. From the thirteenth hour the cost is 0.20 € per hour. We did this following a cruise we took in 2008. I checked my notes and we paid 3.80 Euro per bag for about 2-3 hours so this seems right. Keep in mind this is per bag. Although we had travelled light (a 21-22 in. roller bag and a carry-on each for 5 weeks), this meant we were checking 7 bags. Finding the room is very easy.

Thanks to everyone for the great advice. This is very helpful for our planning. Thank you.

We used the luggage facility in July 2010 so can confirm it's by track 1. It is secure and well organized but the lines for drop off and pickup can be very long. VERY long; a 45-minute lineup is not uncommon. So don't cut your timing too fine - be sure to leave plenty of time before your train departure.