Astitva – Ek Prem Kahani (transl. 'Existence – a love story') was a Hindi-language soap opera that aired on Zee TV channel for more than three years. The story focuses on the concept of a woman's identity through the character of Dr. Simran, who embodies patience, consistency, and suppression in a subtle way. She is a gynecologist who enters a complex situation when she marries a man ten years younger than herself. It shows the ensuing struggles in her life.
 Dr. Simran Mathur, a renowned gynecologist, is the eldest daughter of senior government officer Saurabh and homemaker Padma. Simran has two younger sisters, Kavita and Rashmi. Simran’s parents worry that their eldest daughter is unmarried and in her mid-thirties.
 Simran operates on a critically ill patient, Anandi, saving her and her baby. Anandi’s brother, Abhimanyu Saxena (Abhi), is smitten by Dr. Simran. Abhi, a photographer, woos Simran, who resists his advances because he is ten years younger than she.
 Eventually, Simran falls in love with Abhi, and when Abhi proposes to her, she agrees. Simran's and Abhi’s parents are against this match because of the age difference. Abhi and Simran elope and get married with the help of Simran’s good friend Dr. Manas. Urmila, Dr. Manas’s wife, is jealous of her husband's friendship with Simran.
 Saurabh renounces his daughter and resigns from his job. He is depressed and angry because he believes his favorite daughter ruined her life, and he finds solace in the arms of his mistress, Anjali. Kavita, who lives at her parents' home with her husband Rohit, reveals that she has always been jealous of Simran for monopolising their father’s attention. Kavita takes this opportunity to get back at Simran by fueling fights with Saurabh.
 Abhi’s parents invite the couple to live with them, but Simran is mistreated at Abhi’s house. Abhi's immaturity causes some friction in their relationship, but the couple is able to work things out. Abhi tastes success at work and employs a new assistant, Kiran. Simran is thrilled to learn that she is pregnant, but Abhi gets nervous about impending parenthood. He starts an extramarital affair with Kiran. Abhi abandons Simran emotionally while she goes through a complicated pregnancy. Simran gives birth to a girl, whom she names Aastha. Abhi wins accolades for his work and rises in his career. He introduces Kiran to his mother, who is impressed. Eventually, Saurabh breaks up with Anjali, and Kavita changes her attitude towards Simran. Soon they learn that Kavita has cancer, and she leaves for Switzerland for her treatment. Abhi marries Kiran after divorcing Simran. Kiran is pregnant with Abhi's child and aborts it on the advice of rich businessman Anil Shourie. Kiran leaves Abhi and goes to live with Shourie. Abhi marries Neha, and she is soon pregnant. Simran helps Neha give birth to a daughter, but shortly after, Neha dies. Simran takes a trip to London with Abhi,where someone kidnaps Aastha. Abhi's family want Simran to look after Neha's daughter. Simran agrees to raise her as her own, naming her Aastha, while Abhi disappears.
 Abhi is a famous writer using the pen name Anand and lives as a recluse in Goa. A girl named Sia meets him, and after some misunderstandings, it is revealed that she is actually Abhi and Simran's daughter Aastha. Sia was raised by the childless and mentally disturbed woman who had kidnapped her. Sia and Abhi reunite, and he takes her to Simran. Simran and Neha's daughter, Aastha, are living as mother and daughter. Aastha grows increasingly jealous as her best friend, Dr. Siddhant, starts to take an interest in Sia. Aastha herself has feelings for Siddhant, who is Manas and Urmila's son. Kiran tries to influence Aastha, who eventually sees through her intentions and reunites with Simran. Sia and Siddhant get engaged. The bus in which Simran and Astha are traveling becomes the target of a bomb blast. Aastha is killed, and Simran loses her eyesight. In the end, Simran gets her eyesight back through surgery. She and Abhi reunite.
 The series had a crossover with Reth.
 2003 3rd Indian Television Academy Awards
 Best Actress (Drama) - Niki Aneja Walia as Dr. Simran Mathur
 Best Director (Drama) - Ajai Sinha
 2005 2nd Apsara Awards
 Best Drama Series - Astitva...Ek Prem Kahani
 Best Actress - Niki Aneja Walia as Dr. Simran Mathur / Saxena
 Best Actor - Varun Badola as Abhimanyu Saxena / Anand
 2005 Indian Television Academy Awards
 Best Actor (Drama) - Varun Badola as Abhimanyu Saxena / Anand
 Best Teleplay - Astitva...Ek Prem Kahani - Gajra Kottary & Purnendu Shekhar