The Manas air base has been a crucial supply line for the US
The US will be able to take non-military supplies bound for Afghanistan through Tajikistan and Uzbekistan, a US commander has said.
Mark Harnitchek said between 50 and 200 containers would be sent via the two countries every week.
The announcement follows a decision by Kyrgyzstan to close a US air base - the only US military base in Central Asia.
The US is concerned that the Taleban is regrouping in Afghanistan and this week promised to send 17,000 more troops.
Rear Admiral Harnitchek is on a visit to the Tajik capital, Dushanbe, to investigate alternate supply routes into Afghanistan following the Kyrgyz decision to close the Manas base.
"Tajikistan has given permission to use its railways and roads for the transit of non-military cargoes to Afghanistan," Harnitchek told Tajik state media.
"We plan to transport 50 to 200 containers every week from Uzbekistan to Tajikistan and further to Afghanistan."
The US recently invested millions of dollars in a bridge connecting Tajikistan and Afghanistan, which will almost certainly be used to transport the supplies.
The US had previously announced it intended to transport supplies to Uzbekistan through Russia and Kazakhstan.
It comes after Kyrgyzstan accused the US of not paying enough to rent the air base at Manas, near the capital city of Bishkek.
The licence to close the base was signed into law this week by Kyrgyz President Kurmanbek Bakiyev.
The Kyrgyz foreign ministry said on Friday that it had officially issued an eviction notice giving the US 180 days to vacate the area.
In a statement, the US embassy in Bishkek said it had not yet received any such notice.
Analysts have suggested that Kyrgyzstan's leaders will not carry out their threat to evict the US, but are using the law as a bargaining chip to get more rent money from Washington.
US Defence Secretary Robert Gates sought to play down the Kyrgyz spat on Thursday, saying the US was open to negotiation on the rent.
"We are prepared to look at the fees and see if there is justification for a somewhat larger payment," he told a news conference.
"But we're not going to be ridiculous about it."
Mr Gates is at a Nato meeting in Poland this week, where he has been pressing his allies to commit more troops to the Afghan conflict.
The 17,000 increase in troop numbers announced earlier this week will bring the number of US forces in Afghanistan to more than 50,000.
EXISTING/POSSIBLE SUPPLY ROUTES TO TROOPS IN AFGHANISTAN
1. Manas airbase: the only US base in Central Asia, a vital transit point for Nato and US operations. Kyrgyz government wants it closed
2. Karshi-Khanabad airbase: US forces were ordered out in 2005. Uzbekistan may agree to allow it to be used for non-military transports
3. Bridge over Panj river: part-funded by the US, it was completed in 2007. May serve as another supply route into Afghanistan
4. Khyber Pass: most supplies to US and Nato troops come through Pakistan. Increasing number of attacks in the area mean the US army is looking for back-up routes