Short answer
Pay it to their heirs, through whoever is handling the estate. The debt does not end with death; it now belongs to the heirs. If, after a real effort, no heir can be found, give the amount in charity on the dead person's behalf, ready to repay the heirs if they ever appear.
A debt owed to the deceased becomes part of his estate and is paid to the heirs (or the executor), not to one heir alone unless the others authorise it. If the owner and heirs cannot be traced after effort, the amount is given in sadaqah on the owner's behalf, and if an heir later claims it, it must be paid and the charity's reward is the payer's.
The four schools agree on this.
Explanation
Perhaps you borrowed from a friend, owed a relative for something, or held a deposit for someone, and now they have passed away. Many people feel unsure who to pay, or quietly let it go. But the right does not die with the person. Allah commands that trusts be returned to their owners, and the Prophet ﷺ warned that unpaid rights are settled on the Day of Judgement with good deeds.
What to do:
- Tell the family or the person handling the estate what you owe. It is part of the estate and will be divided among the heirs by their shares.
- Pay the executor or all the heirs together, not just one of them, unless the others agree. Paying one heir only clears his share.
- Keep a record of what you paid and to whom.
If you cannot find the heirs. Make a real effort: ask the mosque, mutual friends and community. If they still cannot be found, give the amount in charity with the intention that the reward goes to the person you owed. If an heir later appears and asks for it, pay them, and the charity becomes your own good deed.
If the heirs forgive it. Adult heirs may forgive their own shares of the debt. A minor's share cannot be forgiven by anyone, so it must be paid to their guardian for them.
If you cannot pay right away, tell the heirs and agree a plan. The Prophet ﷺ said that whoever takes people's money intending to repay it, Allah will help him repay. If the dead person owed you money instead, see paying the debts of the dead.
The evidence
Quran, Surah An-Nisaa 4:58
۞ إِنَّ ٱللَّهَ يَأْمُرُكُمْ أَن تُؤَدُّوا۟ ٱلْأَمَٰنَٰتِ إِلَىٰٓ أَهْلِهَا وَإِذَا حَكَمْتُم بَيْنَ ٱلنَّاسِ أَن تَحْكُمُوا۟ بِٱلْعَدْلِ ۚ إِنَّ ٱللَّهَ نِعِمَّا يَعِظُكُم بِهِۦٓ ۗ إِنَّ ٱللَّهَ كَانَ سَمِيعًۢا بَصِيرًۭا ﴿٥٨﴾
Indeed, Allah commands you to render trusts to whom they are due and when you judge between people to judge with justice. Excellent is that which Allah instructs you. Indeed, Allah is ever Hearing and Seeing.
What you owe must reach its rightful owner, now the heirs.
Quran, Surah Al-Baqara 2:283
۞ وَإِن كُنتُمْ عَلَىٰ سَفَرٍۢ وَلَمْ تَجِدُوا۟ كَاتِبًۭا فَرِهَٰنٌۭ مَّقْبُوضَةٌۭ ۖ فَإِنْ أَمِنَ بَعْضُكُم بَعْضًۭا فَلْيُؤَدِّ ٱلَّذِى ٱؤْتُمِنَ أَمَٰنَتَهُۥ وَلْيَتَّقِ ٱللَّهَ رَبَّهُۥ ۗ وَلَا تَكْتُمُوا۟ ٱلشَّهَٰدَةَ ۚ وَمَن يَكْتُمْهَا فَإِنَّهُۥٓ ءَاثِمٌۭ قَلْبُهُۥ ۗ وَٱللَّهُ بِمَا تَعْمَلُونَ عَلِيمٌۭ ﴿٢٨٣﴾
And if you are on a journey and cannot find a scribe, then a security deposit [should be] taken. And if one of you entrusts another, then let him who is entrusted discharge his trust [faithfully] and let him fear Allah, his Lord. And do not conceal testimony, for whoever conceals it - his heart is indeed sinful, and Allah is Knowing of what you do.
A trust must be fulfilled faithfully.
Sahih al-Bukhari 2449
Sahih... فليتحلله منه اليوم قبل أن لا يكون دينار ولا درهم ...
"Let him settle it today, before there is neither dinar nor dirham."
Unpaid rights must be settled in this life.
Sahih al-Bukhari 2387
Sahih... من أخذ أموال الناس يريد أداءها أدى الله عنه ...
"Whoever takes people's money intending to repay it, Allah will repay it for him."
A sincere intention to repay brings Allah's help.
Where the ruling is recorded
- Radd al-Muhtar (Ibn Abidin), Kitab al-Luqatah and Kitab al-Fara'id. Giving in charity on the owner's behalf when the owner cannot be found, and liability if he appears.
- al-Fatawa al-Hindiyya, Kitab al-Fara'id, debts owed to the deceased. Paying an heir clears only his share.
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.