The Home Office revealed 61 self-harm incidents requiring medical treatment at Yarl's Wood near Bedford in 2014 - but that was down from 74 in 2013.
The centre houses nearly 400 detainees and most are women.
Medical Justice, which sends volunteer doctors and campaigns for the release of vulnerable people from detention, described the figures as "worrying".
Emma Ginn, co-ordinator at Medical Justice, said: "Our volunteer doctors visit immigration detainees and have seen hundreds of cases of seriously inadequate healthcare.
"In many cases immigration detention exacerbates existing medical conditions and in some cases has been the cause of mental illness."
Conservative MP for Bedford Richard Fuller said he wanted the Home Office to look at whether vulnerable asylum seekers who claimed to have been tortured or abused should be housed in detention centres, even if they could not prove their allegations.
"Just because you cannot prove that you were a victim of torture or rape doesn't mean it did not happen," he said.
"This is an issue I would strongly urge the Home Office to look at."
The figures were revealed by Home Office Minister Lord Bates in response to a written parliamentary question but he said they were a "collation of incidents".
"They do not necessarily equate to the number of detainees requiring medical attention as one individual may have received medical attention on more than one occasion," Lord Bates said.
Home Secretary Theresa May has ordered a review of detainees' welfare and former prisons ombudsman Stephen Shaw is due to report back in August.
Shadow home secretary Yvette Cooper said women who have been sexually abused, tortured or are pregnant should not be detained.
Vulnerable detainees held at a centre while awaiting deportation are self-harming, official figures have shown.