As Per Wikipedia :(extracted because of the beautiful explanation of the whole thing)
Hanuman (also known as Anjaneya and Maruti) is a Hindu deity and an ardent devotee of Lord Rama, a central character in the Sanskrit epic Ramayana. The qualities of Hanuman, his strength, courage, wisdom, celibacy, devotion to Rama and the many names by which he was known is detailed in Hanuman Chalisa. There are more temples devoted to Hanuman than any other deity in India and recitation of Hanuman Chalisa is one of the common religious practices.
Hanuman (Sanskrit: हनुमान्, Hanumān), is a Hindu deity who is an ardent devotee of Rama, the seventh avatar of Lord Vishnu, and a central character in the Indian epic Ramayan. A general among the vanaras, Hanuman is a disciple of Lord Rama in the war against the demon king Ravan. Hanuman's exploits are much celebrated in a variety of religious and cultural traditions, particularly in Hinduism, to the extent that he is often the object of worship according to some bhakti traditions, and is the prime deity in many temples known as Hanuman Mandirs.
Swami Vivekananda on Hanuman Chalisa
You have now to make the character of Mahavira your ideal. See how at the command of Ramachandra he crossed the ocean. He had no care for life or death! He was a perfect master of his senses and wonderfully sagacious. You have now to build your life on his great ideal of personal service. Through that, all the other ideals will gradually manifest in life. Obedience to Guru without questioning, and strict observance of Brahmacharya - this is the secret of success. As on the one hand Hanuman represents the ideal of service, so on the other he represents leonine courage, striking the whole world with awe. He has not he least hesitation in sacrificing his life for the good of Rama. A supreme indifference to everything except the service of Rama, even to the attainment of the status of Brahma and Shiva, the great World-Gods! Only the carrying out of Shri Rama's best is the one vow of this life! such whole-hearted devotion is wanted.
As a Hindu and a practitioner of Spiritual Practices, I have always enjoyed reading this divine poem and have benefited in several ways. Many of my accomplishments, have been possible, with the regular reading of Hanuman Chalisa.
This poem has got great Spiritual Powers hidden in it, which can be felt, if practiced daily. My own experience; the practice of reading this holy poem can dramatically change things for our betterment, around us.
I have experienced, people attaining spiritual wisdom and gained super confidence in life. It is a one stop solution for all kinds of fear, worries, weakness, low esteem, knowledge and intelligence.
Reading Hanuman Chalisa before going for any job interviews boosts confidence and helps to stay focused.
It is believed that reading Hanuman Chalisa everyday will save one from all kinds of dangers and evil spirits.
Reading Hanuman Chalisa on Tuesdays and Saturdays has got special benefits because these are the two days, as per Hindu mythology, that belong to Lord Hanuman and Saturn.
The extra ordinary Spiritual Powers hidden in this Devine poem can be only be felt, by reading it every day with full devotion .
Jai hanuman gyan gun sagar|Jai kapise tehu lok ujagar ||
Ram dut atulit bal dhama |Anjani putra pavan sut nama ||
Mahabir bikram bajragee |Kumati nivas sumati ke sangi ||
Kanchan baran biraj subesa |Kann kundal kunchit kesa ||
Haat vajar ao dheja biraje |Kandhe muj janeu sajee ||
Sankar suvan kesrinandan |Tej pratap maha jag bandhan ||
Vidhyavan gune aati chatur |Ram kaaj kaibe ko aatur ||
Prabhu charit sunibe ko rasiya |Ram lakhan sita maan basiya ||
Susham roop dhari siyahi dhikhava |Bikat roop dhari lank jarava ||
Bhim roop dhari asur sahare |Ramchandra ke kaaj savare ||
Laye sanjeevan lakhan jiyaye |Shriraghuvir harsha ure laye ||
Raghupati kinhe bahut badai |Tum mam preye bharat sam bhai ||
Sahart badan tumarhu jas gavey |Aas kahi shripati kant lagavey ||
Sankadeek bhramadhi munisa |Narad sarad sahit ahisa ||
Jam kuber digpal jaha thi |Kavi kovid kahi sake kaha thi ||
Tum upkar sughuv kehina |Ram milaye raj pad denha ||
Tumraho mantra vibhekshan mana |Lankeshvar bhaye sab jag jaan ||
Jug sahes jojan per bhanu |Linyo tahi madhur phal janu ||
Prabhu mudrika meli mukh mahi |Jaldhi ladhi gaye acraj nahi ||
Durgam kaaj jagat ke jete |Sugam anugrah tumre tete ||
Ram duaare tum rakhvare |Hoot na aagya binu pasare ||
Sab sukh lahai tumhre sarna |Tum rchak kahu ko daarna ||
Aapan tej samharo aape |Teno lok hakte kape ||
Bhut pesach nikat nahi aaveh |Mahavir jab naam sunaveh ||
Nase rog hare sab peera |Japat nirantar hanumat bal bira ||
Sankat se hanuman chudave |Maan kam bachan dayan jo lavey ||
Sab per ram tapasvi raja |Tin ke kaaj sakal tum saja ||
Aur manorat jo kayi lave |Tasuye amit jeevan phal pavey ||
Charo guj pratap tumarah |Hai prasidh jagat ujeyara ||
Sadhu sant ke tum rakhvare |Asur nikandan ram dulare ||
Ashat sidhi navnidhi ke data |As var deen jaanki mata ||
Ram rasayan tumhre pasa |Sada raho raghupati ke dasa ||
Tumreh bhajan ram ko bhavey |Janam janam ke dukh bisravey ||
Ant kaal raghubar pur jaie |Jaha janam hari bhagat kahaei ||
Aur devta chitna dhareyo |Hanumat seye sarav sukh karaei ||
Sankat kate mite sab pera |Jo sumere hanumat balbira ||
Jai jai jai hanuman gusai |Kripa karo guru dev ke naai ||
Jo sat bar pat kar koi |Chutehi bandhi maha sukh hoai ||
Jo yahe pade hanuman chalisa |Hoye sidhi sa ke goresa ||
Tulsidas sada hari chera |Kijeye nath hridaye maha dera ||
Doha: Read this, after reading the poem to complete the whole hymn.
Pavantnaye Sankat Haran, Mangal Murti Roop |
Ram Lakhan Sita sahit, Hridaye Basahu Sur Bhup ||
Jai Sri Ram| Pavansut Hanuman Ji ki Jai|