loc and iloc are used for selection and indexing in Pandas. loc is label-based, meaning you specify the row and column labels, while iloc is integer-location based, where you provide the integer index of the rows and columns. For example, df.loc[1, 'column_name'] selects the value at the intersection of the first row and the specified column, while df.iloc[0, 1] selects the value at the first row and second column.