This book describes the modification and characterization of carbon paste modified electrode for the detection of analytes such as Dopamine (DA), Ascorbic acid (AA), Uric acid (UA), Folic acid and Paracetamol in biological buffer solution. Dopamine (DA), 3, 4-dihydroxyphenylethylamine is an important naturally occurring neurotransmitter in the mammalian central nervous system. A deficiency in this catecholamine level can cause some serious diseases such as Parkinson, epilepsy and senile dementia in humans. Uric acid (UA) is the primary end product of purine metabolism in the human body. In a healthy human being, the typical concentration of UA in urine is around 2 mM and in the blood is in between 120 ?M to 450 ?M ranges. Electrochemical analysis on the modified electrodes represents a modern approach to electrode systems. They alter the electrode surface by means of a reagent placed on the electrode surface. Such deliberate alterations can thus meet these needs and can be beneficial to many electroanalytical problems. The work carried out in the above topic is divided and described into seven chapters.