Opposed to democracy, secularism and nationalism, SIMI has been advocating among its followers - some 400 ansars (full-time cadres) and the 19,000 ordinary members - the need to oppose "man-made" institutions and work for the ummah (Muslim brotherhood). The cadres of SIMI consider the Afghanistan-based Osama bin Laden as a ‘true believer of Islam’ and look up to him as an epitome of ‘Islamic Hero’. According to Safdar Nagouri, General Secretary of SIMI, the outfit believes that Osama bin Laden is "not a terrorist'" and neither is Jammu and Kashmir an "integral part of India." At its congregations, messages and recorded speeches have been relayed from the Palestinian Hamas leader Sheikh Ahmed Yasin and Qazi Hussein Ahmed, the Amir of the Pakistani Jamaat. SIMI is widely believed to be against Hinduism, western beliefs and ideals, as well as other anti-Islamic cultures. Among its various objectives the SIMI aims to counter what it believes is the increasing moral degeneration, sexual anarchy in the Indian society as also the ‘insensitiveness’ of a ‘decadent’ west.

SIMI publishes several magazines in various languages which include Vivekam (Malayalam), Sedhi madal (Tamil), Rupantar (Bengali), Iqraa (Gujarati), Tahreek (Hindi) and Al Harkah (Urdu). The outfit is currently regarded as having a national presence with strong bases in Uttar Pradesh, Delhi, Madhya Pradesh, Gujarat, Kerala, Maharashtra, Andhra Pradesh and Assam. The SIMI is being utilised by various terrorist outfits because it has a well-knit network in UP, Bihar and West Bengal. News reports indicate that terrorist outfits had also found a fertile ground in the SIMI for the recruitment of new sympathisers.

SIMI is believed to enjoy the support of a large section of the Muslim populace in cities such as Kanpur, Rampur, Moradabad, Saharanpur, Lucknow and Azamgarh in Uttar Pradesh. Two SIMI activists and their three associates were arrested in Lucknow in September 2000 for delivering inflammatory speeches and inciting communal violence in the city. Official sources are reported to have identified nine districts in Uttar Pradesh where the SIMI is suspected of engaging in subversive activities - Lucknow, Kanpur, Aligarh, Agra, Faizabad, Bahraich, Barabanki, Lakhimpur Kheri and Azamgarh. It is also alleged that 12 SIMI cadres, some of them students at the Aligarh Muslim University had abducted and tortured a Deputy Superintendent of Police attached with the local branch of the Intelligence Bureau.

The Deputy Chief Minister of Maharashtra, Chhagan Bhujbal disclosed in the State Legislative Assembly on March 12, 2001, that the Karachi-based mafia chief, Chhota Shakeel in league with the Students Islamic Movement of India was inciting communal riots in some parts of the State. Sajid Sundke, the city unit chief of SIMI and four of his associates were arrested in Pune on March 11, 2001, for their suspected involvement in communal riots in Ganj Peth and Ghorpade Peth areas of the city. Ilyas Gausn, main accused in the communal violence surrendered before a judicial magistrate on April 10, 2001. The police had registered a case against Gaus on charges of fanning communal passions by making inflammatory speeches during the Friday prayers on March 1, 2001 at a mosque in the Ghorpade Peth area of the city and distribution of pamphlets. The Maharashtra government has confirmed SIMI's role in creating law and order problems in 21 different cases in the State in which 206 cadres of the outfit have been arrested. On May 9, 2001, the police arrested 13 SIMI activists, including zonal President Irshad Khan in Kurla and Vikhroli for allegedly possessing weapons (choppers) and several incriminating documents. The police alleged that among the seized documents were texts of speeches, which were reportedly intended to create communal tension in Mumbai. The State Deputy Chief Minister Chhagan Bhujbal, who also holds the home portfolio, told the Legislative Assembly that the State government had asked the Centre to proscribe the SIMI for its anti-national activities. SIMI activists were involved in the untoward incidents that occurred at various places in Maharashtra over the screening of controversial Hindi film ‘Gadar’. Eleven cases had been registered and 68 persons arrested in the incidents that had taken place in cinema halls in Sangamner, Washim, Parali and Bhiwandi leading to riots, communal tension and the death of one person.

In the March 16, 2001 clash between SIMI activists and the police in Kanpur six persons including an Additional District Magistrate were killed. Violence erupted when the police prevented SIMI activists from assembling at the Parade Choraha immediately after the Friday prayers to register their resentment against the alleged burning of Quran in New Delhi. Mohammad Aquil, a former student of Aligarh Muslim University (AMU) and an active member of the SIMI was arrested by the UP Police in a bomb blast case, which occurred on August 15, 2000 in the Sabarmati Express near Faizabad. The bomb blast had caused the death of 10 passengers and had injured 40 others.

The SIMI in also alleged to be responsible for the twin blasts in Delhi on May 9, 2001 in which one person was injured. The first bomb went off near the Army Headquarters and another bomb exploded in a parking lot on Dalhousie Road.

The Gujarat government in a letter to the Union Home Ministry called for a ban on SIMI on the basis of the anti-national activities of the outfit in the state. The State police in May 2001 had arrested many SIMI leaders in Bhuj on the charges of arousing a communal flare up. The police had also invoked stipulations of the National Security Act against SIMI in Kutch after the cadres were found selling posters of Maulana Masood Azhar, Chief of the Pakistan-based Jaish-e-Mohammed (JeM) who had been released in the terrorists-for-hostages swap in Kandahar.