This section of the article is an erratum for the paper "Prediction of Protein Cellular Attributes Using Pseudo-Amino Acid Composition" by Kuo-Chen Chou, published in *PROTEINS: Struct Funct Genet* in 2001. The erratum addresses three specific issues: 1. All instances of the symbol λ in Figure 1 on page 247 should be replaced by Θ. 2. After Equation 1 on the same page, the following text should be inserted: "where R1 represents the residue at sequence position 1, R2 the residue at position 2, and so forth. The sequence order ...". 3. Equation 10 should be corrected to read: \[ x_i^k = \frac{1}{n_\xi} \sum_{k=1}^{n_i} x_{k,i}^k, \quad (i = 1, 2, \ldots, 20 + \lambda). \]This section of the article is an erratum for the paper "Prediction of Protein Cellular Attributes Using Pseudo-Amino Acid Composition" by Kuo-Chen Chou, published in *PROTEINS: Struct Funct Genet* in 2001. The erratum addresses three specific issues: 1. All instances of the symbol λ in Figure 1 on page 247 should be replaced by Θ. 2. After Equation 1 on the same page, the following text should be inserted: "where R1 represents the residue at sequence position 1, R2 the residue at position 2, and so forth. The sequence order ...". 3. Equation 10 should be corrected to read: \[ x_i^k = \frac{1}{n_\xi} \sum_{k=1}^{n_i} x_{k,i}^k, \quad (i = 1, 2, \ldots, 20 + \lambda). \]