In July this year, 90.3% of patients spent four hours or less in A&E, missing NHS England's 95% target, which was last achieved in July 2015.
There were also 500,498 emergency admissions in July 2017, which is only the third time since records began that emergency admissions have topped half a million, and the first time July emergency admissions have done so.
A spokesman for NHS England said nine out of 10 patients were being admitted, treated, and transferred or discharged from A&E within four hours, which was "up on the May 2017 performance".
He said: "Reducing delays for patients awaiting discharge from hospital remains a key priority ahead of winter, and it is positive that NHS-related delays are lower this year than last."
The latest figures also show that in June, two of NHS England's eight cancer targets were not met either, including the 85% standard for 62 days between referral from a GP and first treatment.
Only 80.5% of patients began their first definitive treatment within 62 days of an urgent GP referral where cancer was suspected.
Lucy Schonegevel, public affairs manager at Macmillan Cancer Support, said: "Timely access to treatment should be a standard part of anybody's cancer journey, but sadly these figures show that this isn't the case for thousands of people each month.
"Waiting to start treatment is often an incredibly difficult time, and should not go on a moment longer than is necessary."