Hastert's retirement would end a political career that included more than seven years as speaker of the House of Representatives. No Republican has held the post longer.
A formal announcement of Hastert's plans is scheduled for Friday.
Hastert's planned retirement is likely to set off a lively scramble between the two political parties for a House seat that he has held easily since 1986.
His decision has been expected since Republicans lost control of the House last November, costing him his powerful post.
The officials who discussed his plans did so on condition of anonymity, saying they did not want to pre-empt a public announcement.