Figures show Sheffield Teaching Hospitals NHS Foundation Trust has not met the 95 per cent threshold of patients being treated at A&E within four hours since June 2015. Latest figures put the Trust at 89.8 per cent - 64th out of 135.
The Trust also haven't met the 85 per cent national target for patients starting cancer treatment within 62 days of urgent GP referral since August 2015. The Trust ranked 121st out of 135 for September with a figure of 75.1 per cent.
But there was better news as latest figures showed Sheffield Teaching Hospitals had a 95.7 per cent rate of seeing patients within 18 weeks or less for planned operations and care. National target is 92 per cent. The fifth best in England.
The stats were compiled by the BBC and compared each of NHS England's 134 hospital trusts.
Sheffield NHS bosses said A&E targets have been met on individual days and added cancer waiting times were lower due to the city being a regional centre having lots of referrals from smaller hospitals.
And Sheffield Unison boss Charlie Carruth said the Government needed to stop obsessing over targets and added staff are 'working miracles in the current circumstances'.
He said: "The reality is the NHS is short staffed and it's not like you can just hire a load of new people straight away plus the general demand is increasing.
"There is no real injection of money to drastically change things so there is no wonder Trusts don't hit national targets. Staff in Sheffield are working miracles in the current circumstances and they're a credit to the NHS.
"Targets are their for a reason but the Government shouldn't be putting too much emphasis on this under the current climate."
Kirsten Major, deputy chief executive at Sheffield Teaching Hospitals NHS Foundation Trust: “Our staff work exceptionally hard to do their very best to provide care for patients in the shortest possible time as well as ensuring the care is of a high standard. In relation to the BBC website figures, we are one of the top five hospital Trusts for ensuring the majority of our patients receive their operation within the 18 weeks national standard.
"In fact our average waiting time is six to eight weeks. Nine out of 10 patients are currently seen, treated and discharged or admitted to a ward within four hours of arriving at A&E. Our waiting time performance for A&E is 92.0% for August and 89.2% in September. On several days in both months we met the 95% standard.
"Patients can also be assured that we also have an exceptional record on cancer waiting times and have consistently met the majority of standards for the past 10 years. The 62 day treatment waiting time standard for non-urgent cancers is lower because we are the regional centre for cancer treatment and so we have referrals from all the local hospitals as well as referrals from further afield.
"We consistently receive these referrals from outside Sheffield towards the end of the 62 day period which leaves less time for us to conduct the specialist tests and provide treatment within the time period.
"We work hard to encourage other hospitals to refer to us as early as possible but regrettably this does not always happen and the effect of this is reflected in our performance and not the other hospitals figures. Without these referrals, we consistently meet the national standard for patients receiving treatment within 62 days for patients whose care starts in Sheffield.”