Short answer
Yes, if it is serious or affects married life: an infectious disease, known infertility, impotence, or a major mental or physical illness. Hiding it is deception, which the Prophet ﷺ condemned. In the Hanafi school the nikah stays valid, and only certain defects in the husband give the wife a right to separation, so honesty before the nikah protects everyone.
Concealing a defect the other side would care about is ghish (deception) and sinful, but it does not make the nikah void. The wife may seek separation through a qadi for the husband's genital defects, such as impotence or castration, and Imam Muhammad added serious diseases such as insanity and leprosy, a view later Hanafi scholars adopted for need. The husband has no right of annulment for the wife's defects, since he can divorce.
Other madhhabs
- Shafi'i
- Either spouse may annul the marriage for listed defects in the other, such as insanity, leprosy, vitiligo, and defects of the genitals that prevent intercourse.
- Hanbali
- Either spouse may annul for listed defects in the other, and some Hanbali scholars extend this to any defect that defeats the purposes of marriage.
Explanation
The Prophet ﷺ said, "Whoever deceives is not of me." Marriage is a far bigger trust than a sale, so hiding something that would change the other person's decision is a serious wrong. He also said there is to be no harm and no returning of harm, which makes knowingly passing on an infection haram.
What should be disclosed:
- Infectious diseases such as HIV, hepatitis B or C, or herpes.
- Known infertility, or a condition that makes pregnancy dangerous.
- Impotence or any condition that prevents intercourse.
- A serious mental illness, epilepsy, or a disability that affects daily life.
- A long-term illness that will need major care.
Minor or past illnesses that have healed and do not affect married life do not need to be raised. Past sins are different: those should stay covered.
How and when. Tell the person, or their wali, before agreeing to marry, once the talks are serious. Give honest, simple facts and invite them to ask a doctor. Many people will still say yes, and a marriage built on honesty has a better start. In some countries premarital health checks are common and help with this.
If it was hidden, the nikah is still valid in the Hanafi school, but the wife may have grounds to seek dissolution in some cases, and the deceiver must repent. Ask a mufti. See impotence and consummation and questions to ask.
Ask a mufti about your own case. This answer explains the general ruling. When the details of your situation matter, as they do here, ask a qualified mufti and give them the full facts. Where to ask a scholar.
The evidence
Quran, Surah Al-Ahzaab 33:70
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ ٱتَّقُوا۟ ٱللَّهَ وَقُولُوا۟ قَوْلًۭا سَدِيدًۭا ﴿٧٠﴾
O you who have believed, fear Allah and speak words of appropriate justice.
Honest, upright speech is a duty.
Sahih Muslim 102
Sahih... من غش فليس مني ...
"Whoever deceives is not of me."
Hiding a defect is deception.
Sunan Ibn Majah 2340
Graded sahih... لا ضرر ولا ضرار ...
"There is to be no harm and no returning of harm."
Knowingly passing on illness is forbidden harm.
Where the ruling is recorded
- al-Hidaya, Kitab al-Talaq, Bab al-'Innin wa Ghayrihi. Which defects give the wife a right to separation, and the views of Abu Hanifa and Imam Muhammad.
- al-Hilah al-Najizah (Ashraf Ali Thanawi), chapters on dissolution for the husband's illness. The later Hanafi adoption of separation for serious disease.
- Minhaj al-Talibin (Nawawi), Kitab al-Nikah, on defects that allow annulment. The Shafi'i list of defects for either spouse.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.