Sayyiduna Abu Barzah (may Allah be pleased with him) said: We asked the Prophet (peace and blessings be upon him) whether an uncircumcised man may perform Hajj to the House of Allah. He (peace and blessings be upon him) said: "No, not until he gets circumcised."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأشربة والحد فيها / 17564