The rupee depreciated 10 paise to 79.88 against the US dollar in opening trade on Wednesday tracking the strength of the greenback in the overseas market and firm crude oil prices.
At the interbank foreign exchange, the rupee opened at 79.83 against the US dollar, then fell to 79.88 against the greenback, registering a decline of 10 paise over the last close.
On Tuesday, the rupee had settled at 79.78 against the American currency.
However, the dollar index, which gauges the greenback's strength against a basket of six currencies, fell 0.16 per cent at 107.02.
Global oil benchmark Brent crude futures advanced 0.13 per cent to USD 104.54 per barrel.
Forex traders said the overnight strength of the dollar, higher oil prices and month-end importers' demand for the dollar are likely to weigh on the domestic unit.
"Investors could refrain themselves from taking large positions ahead of monthly expiry and the US Fed decision in the evening,"
Sriram Iyer, Senior Research Analyst at Reliance Securities, said.
On the domestic equity market front, the 30-share Sensex was trading 49.34 points or 0.09 per cent lower at 55,219.15 points while the broader NSE Nifty was down 21.90 points or 0.13 per cent to 16,461.95 points.
Foreign institutional investors remained net sellers in the capital market on Tuesday as they offloaded shares worth Rs 1,548.29 crore, as per exchange data.