This was following a 200 bps hike in February that was designed to halt a slide in the country's cedi currency.
Central Bank Governor Henry Kofi Wampah said the government risked missing its inflation target for 2014 and pressure on growth from external factors remained but the bank would hold the rate steady for now.
"The committee is of the view that the impacts from the recent monetary policies are still working through the system and so it has decided to maintain the policy rate at 18 percent," Wampah told a news conference, referring to measures introduced over the last few months.
Ghana's high growth rates aided by exports of cocoa, oil and gold and its stable democracy have given it a reputation as one of Africa's strongest economies. But the government is wrestling to restore fiscal stability.
It faces a budget deficit that stood at 10.8 percent in 2013. The cedi currency slid around 20 percent last year and has lost around 10 percent since January.
Inflation was running at 14 percent in February and Wampah on Wednesday revised the 2014 target to around 12 pct, above the initial target of 9.5 percent plus or minus 2 percent outlined in the government's annual budget in November.
Some analysts say President John Mahama's government needs to introduce fresh policies to restore fiscal balance.
Finance Minister Seth Terkper announced no new policies to tackle the deficit in a speech to parliament on Tuesday and said measures already introduced, which include subsidy cuts and new foreign exchange rules, would over time consolidate the fiscal position.
"There has been some reduction in the measured rate of inflation since the measures were introduced but we are not satisfied with that. We noted that there are still vulnerabilities," Wampah said.