At 1420 GMT, the rouble was nearly 1 percent weaker against the dollar at 64.31, its lowest since April 16, and had lost 0.65 percent to trade at 71.96 versus the euro .
Analysts attributed the rouble's woes to general trends on emerging markets that have seen equity markets slip and currencies weaken.
"The negative background on emerging markets is weakening the effect of the tax and oil drivers," said analyst Alexander Bakhtin of BCS brokerage.
The rouble usually received a boost from month-end taxes, which often prompt export-focused companies to convert their foreign currency to meet local duties.
The rouble showed little reaction to investors' preparations to buy the OFZ government bonds that the finance ministry auctions weekly.
On Wednesday, Russia sold a combined 58.99 billion roubles ($917.4 million) worth of OFZ bonds maturing in April 2030 and July 2024 in auctions that in the past often helped the Russian currency.
Demand for the two rouble-denominated bonds reached $2.04 billion, close to the record of $2.13 billion it had sold earlier this month.
Demand for these bonds, which serves as a gauge for global sentiment toward Russian assets, have soared in recent months after uncertainty surrounding possible new US sanctions on holdings of Russian debt.
Central bank data shows foreign investors have increased their share of OFZ bond holdings to 26.7 percent as of April 1, their highest level since early August.
Russia's economy ministry said this week that inflows of foreign funds into OFZ bonds will support the rouble this year despite a projected drop in oil prices.
The rouble also has been buttressed in recent weeks by high oil prices, which hovered around six-month highs on Wednesday.
Investors are awaiting the Russian central bank's rate-setting meeting on Friday, where analysts expected it to hold the key rate at 7.75 percent. Russian stock indexes were down.
The dollar-denominated RTS index was down 1.48 percent to 1,258.83 points. The rouble-based MOEX Russian index was 0.70 percent lower at 2,569.56 points.