The purpose of this study is to assess reactogenicity and safety of simultaneous administration of GSK Biologicals' inactivated poliomyelitis vaccine Poliorix and GSK Biologicals' DTPa-vaccine Infanrix vaccines in healthy children in Russian Federation in their first year of life according to National Calendar of Prophylactic Immunisation of Russian Federation.

Inclusion Criteria:

• Subjects who the investigator believes that their parents/guardians can and will comply with the requirements of the protocol should be enrolled in the study.
• A male or female aged 3 months including at the time of the vaccination.
• Written informed consent obtained from the parent of the subject.
• Healthy subjects as established by medical history and clinical examination and thermometry before entering into the study, that don't have contraindications for vaccination against diphtheria, tetanus, pertussis and poliomyelitis

Exclusion Criteria:

• Use of any investigational or non-registered product (drug or vaccine) other than the study vaccines within 30 days preceding the booster dose of study vaccine, or planned use during the study period.
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs from birth.
• Administration of immunoglobulins and/or any blood products from birth or planned administration during the study period.
• Planned administration/ administration of a vaccine not foreseen by the study protocol within 30 days of the vaccination, except recombinant hepatitis B vaccine, Haemophilus influenzae type B vaccine and seasonal/pandemic influenza prophylactic.
• Participation in another clinical study at any time during the study, in which the subject has been or will be exposed to an investigational or a non-registered product (pharmaceutical product or device).
• Previous vaccination against diphtheria, tetanus, pertussis and poliomyelitis if by any reasons it was made in timeframe not stated by National Calendar of Prophylactic Vaccines of Russian Federation.
• Medical history of convulsions and progressive neurological disease.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on physical examination (no laboratory testing required).
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccines.
• Chronic diseases and serious congenital defects.
• Acute disease at the time of enrolment.

Serious Adverse Events: From Day 0 to Month 4; Solicited local and general symptoms: During the 4-day (Days 0-3) post-vaccination period; Unsolicited symptoms: During the 31-day (Days 0-30) post-vaccination period.

For this study, the Total Number (#) of Participants Affected by Other (non-serious) Adverse Events (AEs) was analyzed separately for expected AEs and for unexpected AEs. A consolidated analysis of all expected and unexpected AEs was not technically possible to be performed and the relevant data are no longer available. Therefore, the Total #Participants Affected in Other Adverse Events Table is currently populated by the highest value of #Participants affected within other AE's table.