At the time of the recording of the band's second album, Curtis's condition was particularly severe, with him enduring a weekly average of two tonic-clonic seizures. On one occasion during these recordings, Curtis's bandmates became concerned when they noted he had been absent from the recording studio for two hours. The band's bassist, Peter Hook, discovered Curtis unconscious on the floor of the studio's toilets, having hit his head on a sink following a seizure. Despite instances such as this, Hook stated that, largely through ignorance of the condition, he, Sumner and Morris did not know how to help. Nonetheless, Hook was adamant that Curtis never wanted to upset or concern his bandmates, and would "tell [us] what [we] wanted to hear" if they expressed any concern as to his condition. In one incident, at a concert held before almost 3,000 people at the Rainbow in Finsbury Park in April 1980, the lighting technicians at the venue—contrary to instructions given to them by Rob Gretton prior to the gig—switched on strobe lights midway through Joy Division's performance, causing Curtis to almost immediately stagger backwards and collapse against Stephen Morris's drum kit in the throes of an evident seizure. He had to be carried offstage to the band's dressing room to recuperate.
Curtis's final live performance with Joy Division was on 2 May 1980 at the High Hall of Birmingham University, and included Joy Division's first and only performance of "Ceremony", later recorded by New Order and released as their debut single. The final song Curtis performed on stage with Joy Division prior to his death was "Digital".
Following Curtis's first definite suicide attempt on 6 April 1980, Tony Wilson and his partner, Lindsay—expressing deep concerns as to Joy Division's intense touring schedule being detrimental to Curtis's physical and mental well-being—invited him to recuperate at their cottage in Charlesworth. While there, he is known to have written several letters to Honoré, proclaiming his love for her as he recuperated.
By early 1980, Curtis's marriage to Deborah was foundering, as she had commenced divorce proceedings after he had failed to cease all contact with Honoré. Curtis enjoyed solitude, but had never been mentally equipped for living alone. He was having difficulty balancing his family obligations with his musical ambitions, and his health was gradually worsening as a result of his epilepsy, thus increasing his dependency upon others. On the evening before his death, Curtis informed Bernard Sumner of his insistence upon seeing his wife that evening. He had also made firm plans to rendezvous with his bandmates at Manchester Airport the following day, before their departure for America.
Curtis' body was cremated at Macclesfield Crematorium on 23 May 1980, and his ashes were buried at Macclesfield Cemetery. A memorial stone, inscribed with "Ian Curtis 18 – 5 – 80" and "Love Will Tear Us Apart", was placed above his ashes. This memorial stone was stolen in mid-2008. A replacement, bearing the same inscription, was placed in the same location. A central "mowing" stone used to hold floral tributes was reported stolen from the grave in August 2019.
The words "Ian Curtis Lives" are written on a wall in Wallace Street, Wellington, New Zealand. The message, which appeared shortly after the singer's death in 1980, is repainted whenever it is painted over. A nearby wall on the same street on 4 January 2005 was originally emblazoned "Ian Curtis RIP", later modified to read "Ian Curtis RIP Walk in Silence" along with the incorrect dates "1960–1980". Both are referred to as "The Ian Curtis Wall". On 10 September 2009, the wall was painted over by Wellington City Council's anti-graffiti team. The wall was chalked back up on 16 September 2009. The wall was repainted on 17 September 2009, and has been removed and repainted on and off. A new and improved design, with correct dates and the original "Walk in Silence", was painted on the wall on 27 February 2013. In October 2020, in line with Manchester music and mental wellbeing festival Headstock, a large mural depicting a black and white portrait of Ian Curtis was painted on the side of a building on Port Street in Manchester's Northern Quarter by street artist Aske.