<p>Oil palm (<em>Elaeis guineensis </em>Jacq.) fruits are classified by shell thickness into three types: <em>dura, pisifera</em>, and <em>tenera</em>, the last one being the product of a <em>dura</em> × <em>pisifera</em> cross. The palm oil industry relies on the use of high-yield <em>tenera</em> plant material for production; however, it is usually generated with female infertile <em>pisifera, </em>so early identification of this trait is very important to oil production and breeding programs. Recently, the mapping and sequencing of the <em>SHELL</em> gene, which is responsible for endocarp formation in oil palms, made it possible to identify two mutations (type SNP, single nucleotide polymorphism) that affect its function and that are useful to developing molecular markers for predicting shell thickness. The aim of this study was to standardize PCR-based methodologies in order to detect the SNP observed in codon 30 and validate it under our <em>E. guineensis</em> biological collections. We achieved the differentiation of SHELL alleles with both allele specific PCR and CAPS with the restriction enzyme <em>Hin</em>dIII in homozygous and heterozygous plants that contained the described mutation, and the prediction was correlated with the phenotype observed in oil palm fruits. These methodologies facilitated the discrimination of plants by fruit type in nursery and pre-nursery stages 24 months before production started, thereby reducing the time and area used in oil palm breeding programs.</p>