"We've accepted his resignation," Ibrahim Megahed told FilGoal.com.
Helmi's decision came few hours after the promoted club suffered a 2-0 defeat to Arab Contractors in the Egyptian Premier League.
They were undone by two second-half goals from Reda Al-Weeshi and Alaa Kamal to suffer their fourth consecutive loss.
Mansoura are now languishing second from bottom with 10 points from 13 games, two adrift of the safety zone.
Helmi told FilGoal.com earlier in the day that he had no choice but to leave the club due to work commitments with EgyptAir, although he was a full-timer at Mansoura.
"We are now looking for a replacement. We've drawn up a list of candidates which include Mohsen Saleh, Mohamed Salah, Theo Buecker and Mostafa Younes."
Former Egypt coach Saleh has recently signed as coach of Saudi side Hazm while German Buecker, who has plenty of experience in Egyptian football, snubbed an opportunity to manage Ittihad.
نرشح لكم
خبر في الجول - عامر والطويل في جهاز عبد الرؤوف مع الزمالك أمام طلائع الجيش
تعادل سلبي جديد.. غزل المحلة ومودرن سبورت يتقاسمان النقاط
الأهلي يكشف سبب غياب محمد علي بن رمضان عن لقاء المصري
قائمة الأهلي – غياب بن رمضان أمام المصري.. وعودة مروان وكوكا
أبو ريدة يهنئ الخطيب لفوزه في انتخابات الأهلي
الزمالك يقيل يانيك فيريرا.. وأحمد عبد الرؤوف بديلا له
حارس إنبي: كنا نستطيع الفوز على الأهلي بسهولة
خبر في الجول - الأهلي يخاطب الجهة الإدارية لاعتماد نتيجة الانتخابات












Mansoura coach Helmi resigns
أكرم توفيق يصنع فوز الشمال بخماسية ضد كارتيرون