Jefferies will take his squad to his favoured summer base at Il Ciocco in Tuscany for a seven-day stay beginning on 10 July.
The players will endure double training sessions each day and a local closed-door friendly match has also been pencilled in to round off the week.
"It's a place I know very well and the facilities are superb," Jefferies told Hearts News.
"The folk are very friendly and the food's excellent as well. I took Hearts there the last time I was here and also went a number of times with Kilmarnock. It's an ideal base for a pre-season training camp and we'll be working the boys hard, that is assured. One thing's for sure – the players will be fit by the time the season starts."