The examination is conducted by the Union Public Service Commission. It has three stages: a preliminary exam, a main exam, and an interview, and is known for being extremely challenging. Recently the preliminary exam pattern has changed. There used to be 23 optional subjects along with a general studies paper. Now there will be no optional subjects in the preliminary examination. Instead there will be a second paper which will be common for all candidates. It covers aptitude, general mathematics, comprehensive English, social studies etc.

Entry into the IAS is considered very difficult. Almost all of the applicants rank IAS as their top choice because of the high prestige and diversity of career it offers. For example, in the 2011 batch, of the 425 selected candidates, 390 indicated IAS as their first preference, 35 chose IRS, and just nine chose IPS. But when it came to second preference, 226 candidates marked IRS as their choice, while only 159 marked IPS as their second choice.

About 850 candidates are finally selected each year out of the nearly 550,000(2010 data) but only a rank in the top 80 guarantees an IAS selection — an acceptance rate of 0.025 percent, which makes it one of the most competitive selection processes in the world.

After being selected for the IAS, candidates are allocated to "cadres." Most IAS officers start their careers in the state administration at the sub-divisional level as a sub divisional magistrate. They are entrusted with the law and order situation of the city along with general administration and development work of the areas under their charge. The post of District Officer is also known as District Magistrate, District Collector or Deputy Commissioner. Since it is the most identifiable position in the IAS services, it is also the post which most people identify with IAS. At the top of the hierarchy of IAS officers at the Centre is the Cabinet Secretary followed by Secretary/Additional Secretary, Joint Secretary, Director, Deputy Secretary and Under Secretary. These posts are filled according to seniority.

DESIRED QUALIFICATION:
The applicants must be degree holders in any discipline from a recognized university and within the age limit as follows:
General Category : Between 21 and 30 years (Get 4 chances to write the exam)
OBC Category : Between 21 and 33 years (Get 7 chances to write the exam)
SC, ST Category : Between 21 and 35 years (No limit)

PROCESS:
The Civil Services Examination of India is considered to be amongst of the most difficult competitive examinations in the world. On an average, 4 to 5 hundred thousand candidates appear for the examination. Aspirants must compete a three-stage process, with a final success rate of about 0.3 % of the total applicants.

Stage I:
Preliminary examination - This is qualifying test held in May/June every year. Notification for this is published in December/January. Results are published in the first half of August.

Stage II:
Main examination - This is the main test, held in October/November every year. Results are usually published in the second week of March.

Stage III:
Personality Test (Interview) - It is the final test and is held in April/May every year. Final results are usually announced a few days before the next preliminary examination.
The training program for the selected candidates usually commences in August every year.