Gianluca Mancini turned in under pressure from Ademola Lookman
Foxes' manager Brendan Rodgers will be disappointed they are not taking a lead to Stadio Olimpico for the second leg after they dominated the second half and came from behind to draw level.
Roma struck early when Nicola Zalewski played in captain Lorenzo Pellegrini for a smooth low finish underneath Leicester keeper Kasper Schmeichel in the 15th minute.
Leicester maintained their composure and deservedly equalised after 67 minutes when Ademola Lookman bundled in a cross from Harvey Barnes, via defender Gianluca Mancini.
Mourinho will be satisfied with this result as Leicester could not make their domination pay, with Roma keeper Rui Patricio saving superbly from lively substitute Kelechi Iheanacho, who also headed over from close range.
Leicester City will believe they did not get the result their performance deserved as Roma defended for the draw which seemed to suit their purposes and those of coach Mourinho.
The Foxes were rocked back by Roma's early goal but get great credit for refusing to panic and continuing to play their passing game which brought the reward of a scrambled equaliser.
Roma's threat was very fleeting, although Schmeichel was called into action in the closing stages to turn substitute Sergio Oliveira's shot on to the woodwork following a clever backheel from England striker Tammy Abraham.
Leicester were tireless, with James Maddison constantly probing despite not having his usual shooting accuracy while Jamie Vardy understandably looked short of full match fitness following his injury absence.
Rodgers has every right to remain positive, however, because Leicester were the better side, were rarely troubled at the back and only lacked cutting edge up front.
Roma, rightly, will feel they are in a favoured position but Leicester will still feel their first appearance in a European final remains a possibility.
-- Courtesy of BBC Sport