The protesters, including villagers in national dress, chanted "Chevron, go home" and "We say no to shale gas."
Chevron on Thursday suspended activities in the region after three days of protests.
But villagers have continued to occupy the site where the company plans to drill its first exploration well.
"We have won a battle but not the final victory. I want my seven great-grand-children to grow up in a safe environment," Emil Dobarteanu, 88, told AFP.
Also Read
The technique consists of pumping water and chemicals at high pressure into deep rock formations to free oil and gas, with environmentalists warning the process may contaminate ground water and even cause small earthquakes.
Film-maker Lech Kowalski, author of "Drill Baby Drill", a documentary about a Polish village fighting against Chevron's shale gas drilling plans, was among the participants.
Several hundred people also protested in the eastern city of Barlad, forming a human chain around the town hall.
Chevron has permits to explore for shale gas in three villages in this impoverished part of northeastern Romania as well as on Romania's Black Sea coast.