Rome to Siena bus?

David,
Notfaster but cheaper http://www.sena.it/

The bus departs from the center of Siena and arrives at Tiburtina Station in Rome. Tiburtina is also a metro stop, which means you can easily reach the city center from this point. The train station in Siena is just outside the center. If you take the train you usually need to transfer trains (typically at Chiusi) and then arrive at Rome's Termini Station, the main station in the center in Rome.

Having traveled this route a number of times, I can tell you that the train is the most convenient choice.

I too am interested in traveling from Siena to Rome. To take the train as you have recommended, does that mean we go to Florence first and then on to Rome? Am I understanding that correctly? Thank you for your help. Annette